matrix is skewsymmetric math begin bmatrix 0 & 2 & 1 2 & 0 & 4 1 & 4 & 0 end bmatrix . math Properties ... identity of the given field. Otherwise, a skewsymmetricmatrix is just the same thing as a symmetricmatrix . Sums and scalar multiples of skewsymmetric matrices are again skewsymmetric. Hence, the skew ... 1 2. Let Mat sub n sub denote the space of nowrap 1 n × n matrices. A skewsymmetricmatrix ... and y . All main diagonal entries of a skewsymmetricmatrix must be zero, so the trace of a matrix ... s as matrix multiplications. Determinant Let A be a n × n skewsymmetricmatrix. The determinant ... Pf A . Thus the determinant of a real skewsymmetricmatrix is always non negative. However this last fact can be proved in an elementary way as follows the eigenvalues of a real skewsymmetricmatrix ... theory The eigenvalue s of a skewsymmetricmatrix always come in pairs except in the odd dimensional case where there is an additional unpaired 0 eigenvalue . For a real skewsymmetricmatrix the nonzero .... Real skewsymmetric matrices are normal matrix normal matrices they commute with their adjoint matrix adjoints and are thus subject to the spectral theorem , which states that any real skewsymmetricmatrix can be diagonalized by a unitary matrix . Since the eigenvalues of a real skewsymmetric ... to bring every skewsymmetricmatrix to a block matrix block diagonal form by an orthogonal matrix orthogonal transformation . Specifically, every 2 n 2 n real skewsymmetricmatrix can be written ... one row and column of zeros. More generally, every complex skewsymmetricmatrix can be written .... Such a will be represented by a skewsymmetricmatrix A , v, w v sup T sup Aw , once a basis linear algebra basis of V is chosen and conversely an n × n skewsymmetricmatrix A on K sup ... is again skewsymmetric math A,B top B top A top A top B top BA AB A,B , . math The matrix exponential of a skewsymmetricmatrix A is then an orthogonal matrix R math R exp A sum n 0 infty frac A n ... more details
symmetric if X is a symmetricmatrix then so is AXA sup T sup for any matrix A . If A is a skew ... matrix Coxeter matrix Hankel matrix Hilbert matrix Persymmetric matrixSkewsymmetricmatrix Toeplitz ...No footnotes date November 2009 In linear algebra , a symmetricmatrix is a square matrix that is equal to its transpose . Let A be a symmetricmatrix. Then math A A top . , math The entries of a symmetricmatrix are symmetric with respect to the main diagonal top left to bottom right . So if the entries ... 3 3 matrix is symmetric math begin bmatrix 1 & 7 & 3 7 & 4 & 5 3 & 5 & 6 end bmatrix . math Every diagonal matrix is symmetric, since all off diagonal entries are zero. Similarly, each diagonal element of a skewsymmetricmatrix must be zero, since each is its own negative. In linear algebra, a real number real symmetricmatrix represents a self adjoint operator over a real number real inner product ... algebra over the complex numbers, it is often assumed that a symmetricmatrix refers to one which ... dimensional spectral theorem says that any symmetricmatrix whose entries are real number real can be diagonal matrix diagonalized by an orthogonal matrix . More explicitly For every symmetric real matrix ... symmetricmatrix is thus, up to choice of an orthonormal basis , a diagonal matrix. Another way to phrase the spectral theorem is that a real n n matrix A is symmetric if and only if there is an orthonormal basis of math mathbb R n math consisting of eigenvectors for A . Every real symmetricmatrix ... to the property of being Hermitian for complex matrices. A complex symmetricmatrix A can often ... of two symmetric matrices is again symmetric, but this is not always true for the matrix multiplication ... of nowrap 1 n × n matrices. A symmetric n × n matrix is determined by n n 1 2 scalars the number of entries on or above the main diagonal . Similarly, a skewsymmetric ... . If Sym sub n sub denotes the space of nowrap 1 n × n symmetric matrices and Skew sub ... more details
Graph families defined by their automorphisms In graph theory , a branch of mathematics, a skewsymmetric ... involution without any Fixed point mathematics fixed points . Skewsymmetric graphs were first ... Goldberg Karzanov 1996 , a skewsymmetric graph G is a directed graph, together with a function ... isomorphism from G to its transpose. However, in a skewsymmetric graph, it is additionally required ... or cycle in a skewsymmetric graph is said to be regular if, for each vertex v of the path or cycle ... A skewsymmetric graph may equivalently be defined in terms of a switch graph to use the terminology ... into two subsets. Each vertex of the switch graph corresponds to two vertices of the skewsymmetric graph, and each edge of the switch graph corresponds to two edges of the skewsymmetric graph ... in terms of skewsymmetric graphs in that application, the two subsets of edges at each vertex are the unmatched ... for a regular path in a skewsymmetric graph. A closely related concept is the bidirected ... bidirected graphs and skewsymmetric graphs see harvtxt Babenko 2006 . To form a skewsymmetric graph ... , v of G , create two directed edges in the skewsymmetric graph, one oriented from u to v and one oriented ... sub 1 sub and into v sub 0 sub . In the other direction, given a skewsymmetric graph G , one may form ... out of and come in to. A regular path or cycle of a skewsymmetric graph corresponds to a path or cycle ... may be modeled as a regular path or cycle in a skewsymmetric directed graph. To create a skewsymmetric ... of a regular path between any two vertices of a skewsymmetric graph may be tested in linear ... in a skewsymmetric graph with m edges and n vertices may be tested in time O m log ... cycle may be tested in polynomial time. Along with the path problems arising in matchings, skewsymmetric ..., and a directed edge for each implication it is, by construction, skewsymmetric, with a correspondence ... . citation last Babenko first Maxim A. contribution Acyclic bidirected and skewsymmetric graphs algorithms ... more details
In linear algebra , skew Hamiltonian matrices are special Matrix mathematics matrices which correspond to skewsymmetric bilinear form s on a symplectic vector space . Let V be a vector space , equipped with a Symplectic vector space symplectic form math Omega math . Such a space must be even dimensional. A linear map math A V mapsto V math is called a skew Hamiltonian operator with respect to math Omega math if the form math x, y mapsto Omega A x , y math is skewsymmetric. Choose a basis math e 1, ... e 2n math in V , such that math Omega math is written as math sum i e i wedge e n i math . Then a linear operator is skew Hamiltonian with respect to math Omega math if and only if its matrix A satisfies math A T J J A math , where J is the skewsymmetricmatrix math J begin bmatrix 0 & I n I n & 0 end bmatrix math and I sub n sub is the math n times n math identity matrix . ref name waterhouse William C. Waterhouse , http linkinghub.elsevier.com retrieve pii S0024379504004410 The structure of alternating Hamiltonian matrices , Linear Algebra and its Applications, Volume 396, 1 February 2005, Pages 385 390 ref Such matrices are called skew Hamiltonian . The square of a Hamiltonian matrix is skew Hamiltonian. The converse is also true every skew Hamiltonian matrix can be obtained as the square of a Hamiltonian matrix. ref name waterhouse ref Heike Fa bender, D. Steven Mackey, Niloufer Mackey and Hongguo Xu http www.icm.tu bs.de hfassben papers hamsqrt.pdf Hamiltonian Square Roots of Skew Hamiltonian Matrices, Linear Algebra and its Applications 287, pp. 125 159, 1999 ref Notes references Category Matrices Category Linear algebra Linear algebra stub it Matrice anti hamiltoniana ... more details
In linear algebra , a square matrix with Complex number complex entries is said to be skew Hermitian ... , 4.1.1 harvtxt Meyer 2000 , 3.2 ref That is, the matrix A is skew Hermitian if it satisfies the relation math A dagger A, math where math dagger math denotes the conjugate transpose of a matrix. In component ... Norm mathematics norm . Example For example, the following matrix is skew Hermitian math begin bmatrix 0 & 2 i 2 i & 0 end bmatrix math Properties The eigenvalues of a skew Hermitian matrix are all purely imaginary. Furthermore, skew Hermitian matrices are normal matrix normal . Hence they are diagonalizable ... Horn Johnson 1985 , 2.5.2, 2.5.4 ref All entries on the main diagonal of a skew Hermitian matrix have ... purely imaginary . ref harvtxt Meyer 2000 , Exercise 3.2.5 ref If A, B are skew Hermitian, then aA bB is skew Hermitian for all real number real scalar mathematics scalars a and b . ref name HJ85S411 harvtxt Horn Johnson 1985 , 4.1.1 ref If A is skew Hermitian, then both iA and iA are Hermitian matrix Hermitian . ref name HJ85S411 If A is skew Hermitian, then A sup k sup is Hermitian if k is an even integer and skew Hermitian if k is an odd integer. An arbitrary square matrix C can uniquely be written as the sum of a Hermitian matrix A and a skew Hermitian matrix B ref name HJ85S412 math C A B quad mbox with quad A frac 1 2 C C dagger quad mbox and quad B frac 1 2 C C dagger . math If A is skew Hermitian, then e sup A sup is unitary matrix unitary . The space of skew Hermitian matrices forms the Lie algebra u n of the Lie group U n . See also Hermitian matrix Normal matrixSkewsymmetric ... sub is the i , j th entry of A , and the overline denotes complex conjugate complex conjugation . Skew Hermitian matrices can be understood as the complex versions of real Skewsymmetricmatrixskewsymmetric matrices , or as the matrix analogue of the purely imaginary numbers. ref name HJ85S412 harvtxt Horn Johnson 1985 , 4.1.2 ref All skew Hermitian var n var var n var matrices form the u var n ... more details
A skew ray optics ray , an optical path through a rotationally symmetric optical system that is not in a plane of symmetry In engineering A skew arch , a method of construction that enables an arch bridge to span an obstacle at some angle other than a right angle In finance Volatility skew, a downward sloping volatility smile In telecommunications Skew fax , the angular deviation of the received ...disambig Wiktionary Skew may refer to In mathematics Skew lines , lines that are neither parallel nor intersecting Skewsymmetricmatrix , a square matrix whose transpose is also its negative Skew Hermitian matrix , a complex square matrix whose conjugate transpose is also its negative Infinite skew polyhedron , an extension of the concept of polyhedra Skewsymmetric graph , a directed graph that is isomorphic to its own transpose graph Skew polygon , a polygon whose vertices do not lie on a plane Skew lattice , a non commutative generalization of a lattice Skew field or division ring , a non commutative ring in which division is possible Skew tableau , a generalization of Young tableau The shear ... of a probability distribution Skew normal distribution , a continuous probability distribution that generalises the normal distribution to allow for non zero skewness In chemistry Skew also ... times of bits recorded in a single transverse line. Skew is usually interpreted to mean the difference .... Skew antenna a method to improve the horizontal radiation pattern In computers Clock skew , a phenomenon ... to computer disk drive s, track to track skew is the angle between the start of the data on a given ..., during which the disk continues to rotate. Insufficient skew can force the drive to wait almost an entire ... to read the data. Excessive skew can also lower the sustained data transfer rate. Transitive data skew In aviate Skew flip turnover , an aircraft maneuver In fantasy baseball SKEW, a strategy that focuses on high impact middle relievers that register a lot of strikeouts de Skew eo Deklivo apartigilo ... more details
to the basic structure theory of skew lattices. Here are several more. SymmetricSkew Lattices A skew lattice S is symmetric if for any math x, y in S math , math x wedge y y wedge x math i math ... S rightarrow S D math being an isomorphism. All symmetricskew lattices for which S D leq aleph ... skew lattices are symmetric and can be shown to form a variety. Unlike lattices, they need not be distributive ... in general for skew lattices, but they are for symmetricskew lattices. See,,. ref name ..., normal skew lattices, and D3 characterizes the variety of symmetric, distributive, normal skew ... distributive skew lattices are categorical. Though symmetricskew lattices might not be. In a sense ... 0 math . 0 A Boolean skew lattice is a symmetric, distributive normal skew lattice with 0, math S vee ... into such an algebra. See. ref name CV05A Cvetko Vah, K, Skew lattices in matrix rings, Algebra ...In abstract algebra , a skew lattice is an algebraic structure that is a non commutative generalization of a lattice order lattice . While the term skew lattice can be used to refer to any non commutative ... A skew lattice is a Set mathematics set S equipped with two associative , idempotent binary ..., Skew lattices in rings, Algebra Universalis, 26 1989 , 48 72. ref center Historical background For over ... paper, Skew lattices in rings , ref name LE89 Leech, J, Skew lattices in rings, Algebra Universalis, 26 1989 , 48 72 ref skew lattices as defined above have been the primary objects of study. This was aided ... properties. Basic properties Natural partial order and natural quasiorder In a skew lattice ... b in B math exist such that math a b math . This permits us to write Hasse diagram s of skew lattices such as the following pair center File Skew diag.png center E.g., in the diagram on the left above ... Skew Lattices Skew lattices consisting of a single math D math class are called rectangular ... vee y y math and math x vee y y wedge x math . Rectangular skew lattices are isomorphic to skew lattices ... more details
An math n math by math n math complex or real matrix math A a i,j 1 leq i, j leq n math is said to be anti Hermitian , skew Hermitian , or said to represent a skew adjoint linear operator operator , or to be a skew adjoint matrix mathematics matrix , on the complex or real math n math dimensional space math K n math , if its adjoint operator adjoint is the negative of itself math A A math . Note that the adjoint of an operator depends on the scalar product considered on the math n math dimensional complex or real space math K n math . If math cdot cdot math denotes the scalar product on math K n math , then saying math A math is skew adjoint means that for all math u,v in K n math one has math Au v u Av , . math In the particular case of the canonical scalar products on math K n math , the matrix of a skew adjoint operator satisfies math a ij overline a ji math for all math 1 leq i,j leq n math . Imaginary number s can be thought of as skew adjoint since they are like 1 by 1 matrices , whereas real number s correspond to self adjoint operators. See also Skew Hermitian matrix Category Abstract algebra Category Linear algebra ... more details
File Regular skew quadrilateral.png thumb An example of a regular skew quadrilateral , with equal edge lengths, and vertex transitive, fitted within a rectangular cuboid . Its interior can be uniquely defined as a bilinear interpolation of the four corners and edges. Here the four equal edges are shown in blue, and equal diagonals in green. In geometry , a skew polygon is a polygon whose vertices do not lie in a plane geometry plane . Skew polygons must have at least 4 Vertex geometry vertices . A regular skew polygon is a skew polygon with equal edge lengths and which is vertex transitive . The interior surface or area of such a polygon is not uniquely defined, although this can be considered as a minimal surface problem like the form of a soap film inside of a wire frame. See also Regular skew polyhedron Infinite skew polyhedron Petrie polygon Apeirogon Skew forms References The Geometrical Foundation of Natural Structure book Skew Polygons Saddle Polygons . 2.2 External links MathWorld title Skew polygon urlname SkewPolygon Category Polygons Geometry stub eo Dekliva plurlatero sl Nagnjen mnogokotnik ... more details
In fax systems, skew is the angular deviation of the received frame from rectangularity caused by asynchronism between the Image scanner scanner and the recorder. This is the same as the angle between the scanning line , or recording line, and the perpendicular to the paper path. ref FS1037C MS188 ref Skew is expressed numerically as the Trigonometric functions tangent tangent of the deviation angle. Image Skew 1 degree.png Example of 1 degree counter clockwise skew in a facsimile image. The red line is perfectly horizontal. References references telecommunications stub Category Fax ... more details
In a synchronous circuit clock skew T sub Skew sub can be defined as the difference in the arrival time ... respectively, then clock skew can be defined as T sub Skew i,j sub T sub C i sub T sub C j sub Clock skew can be positive or negative. If the clock signals are in complete synchronicity, then the clock skew observed at these registers is zero. In circuit design In circuit designs, clock skew sometimes timing skew is a phenomenon in synchronous circuit s in which the clock signal sent from the clock ... of clock skew negative skew and positive skew . Positive skew occurs when the transmitting register receives the clock earlier than the receiving register. Negative skew is the opposite the receiving register gets the clock earlier than the sending register. Harmful skew Two types of violation can be caused by clock skew. One problem is caused when the clock travels more slowly than the path from ... because it cannot be fixed by increasing the clock period. Positive skew and negative skew cannot negatively impact setup and hold timing constraints respectively see inequalities below . Beneficial skew Clock skew can also benefit a circuit by increasing the clock period locally at which the circuit ... time of the destination register, math s d s s math represents the clock skew from the source to the destination registers, math s d math is the clock skew to the destination register, and math s s math is the clock skew to the source register. Positive clock skews are good for fixing setup ... skew describes the difference in time shown by the clocks at the different nodes on the network. It is usually an unavoidable phenomenon at least if one looks at milli second resolutions , but clock skew ... are comparable across hosts can be affected by clock skew. A number of protocols e.g. Network Time Protocol have been designed to reduce clock skew, and produce more stable functions. Some applications ... due to clock skew. Interfaces Clock skew is the reason why at fast speeds, serial interfaces e.g. ... more details
In mathematics , a bisymmetric matrix is a square matrix mathematics matrix that is symmetric about both of its main diagonals. More precisely, an n n matrix A is bisymmetric if it satisfies both A A sup T sup and AJ JA where J is the n n exchange matrix . For example math begin bmatrix a & b & c & d & e b & f & g & h & d c & g & i & g & c d & h & g & f & b e & d & c & b & a end bmatrix . math Properties Bisymmetric matrices are both symmetric centrosymmetric matrix centrosymmetric and symmetric persymmetric matrix persymmetric . It has been shown that real valued bisymmetric matrices are precisely those symmetric matrices whose eigenvalues are the same up to sign after pre or post multiplication by the exchange matrix ref name simax0 cite journal last Tao first D. coauthors Yasuda, M. title A spectral characterization of generalized real symmetric centrosymmetric and generalized real symmetricskew centrosymmetric matrices journal SIAM J. Matrix Anal. Appl. volume 23 issue 3 pages 885 895 year 2002 url http siamdl.aip.org getabs servlet GetabsServlet?prog normal&id SJMAEL000023000003000885000001&idtype cvips&gifs Yes accessdate 2007 10 12 doi 10.1137 S0895479801386730 ref . The product of two bisymmetric matrices results in a centrosymetric matrix References reflist DEFAULTSORT Bisymmetric Matrix Category Matrices eu Matrize bisimetriko sl Bisimetri na matrika th ... more details
In statistics and probability theory , the nonparametric skew is a statistic occasionally used with random variable s that take real values. ref name Rubio2012 Rubio FJ, Steel MFJ 2012 On the Marshall Olkin transformation as a skewing mechanism. Computational Statistics & Data Analysis http www2.warwick.ac.uk fac sci statistics staff academic research steel steel homepage techrep mosrevcsda.pdf Preprint ref Its calculation does not require any knowledge of the underlying distribution hence the name nonparametric. Although its use has been recommended in older textbooks ref name Yule1950 Yule GU, Kendall MG 1950 An Introduction to the Theory of Statistics. 3rd edition. Harper Publishing Company pp 162 163 ref ref name Hildebrand1986 Hildebrand DK 1986 Statistical thinking for behavioral scientists. Boston Duxbury ref it appears to have gone out of fashion. It has been shown to be less statistical power powerful clarify reason less powerful for what purpose? date January 2012 than the usual measures of skewness . ref name amstat cite journal title Measuring Skewness A Forgotten Statistic? first1 David P. last1 Doane first2 Lori E. last2 Seward journal Journal of Statistics Education volume 19 issue 2 year 2011 url http www.amstat.org publications jse v19n2 doane.pdf ref Definition It is defined as S mean &minus median standard deviation where the mean , median and standard deviation of the sample or population have their usual meanings. It is one third of the Pearson 2 skewness ... 3 is from this formula in 1901 leading to the nonparametric skew statistic. Notes The rule ... applied to slightly non symmetric distributions that resemble a normal distribution but it is not always ... v13n2 vonhippel.html Mean, Median, and Skew Correcting a Textbook Rule . ref It is however known that for unimodal ... 1 but the skew 0.906 as defined by the third standardized moment is positive. The distribution ... 7, Mathematisch Centrum, Amsterdam ref The nonparametric skew does not satisfy these axioms. References ... more details
Primarysources date July 2007 Skew Siskin are a German hard rock band best known for their 1992 song If The Walls Could Talk , which was a minor hit on MTV . Fronted by Nina C. Alice , Siskin have been through many lineup changes over their career with Jim Voxx being the only other consistent member. Siskin have released six studio albums and one compilation album in their career since 1992. Lemmy from Mot rhead has often contributed to Siskin albums, and Siskin have contributed to his in progress solo album. ref http www.roadrunnerrecords.com blabbermouth.net news.aspx?mode Article&newsitemID 17676 Blabbermouth.net MOT RHEAD s LEMMY Records Second Solo Track With SKEW SISKIN Dec. 28, 2003 ref . Siskin toured with Motorhead in 2010. Discography Skew Siskin album Skew Siskin 1992 Electric Chair Music 1996 Voices from the War 1996 What the Hell 1999 Album of the Year Skew Siskin Album of the Year 2003 Devil s Disciple album Devil s Disciple compilation 2005 Peace Breaker 2007 External links http www.skewsiskin.net Official Site http www.myspace.com skewsiskin Official MySpace http bnrmetal.com groups sksi.htm BNR Metal Pages Profile & Discography http cdbaby.com cd skewsiskin2 CD Baby profile of Peace Breaker including band history http ia310820.us.archive.org 2 items revolutionart issue 16 revolutionart issue 16.zip Interview With Nina C. Alice in Revolutionart Magazine 16 References references Category German hard rock musical groups Category Mot rhead it Skew Siskin de Skew Siskin pt Skew Siskin ... more details
File Nested hyperboloids.png thumb 300px A fiber bundle fibration of projective space by skew lines on nested hyperboloid s. In solid geometry , skew lines are two lines that do not intersect and are not Parallel ... of a pair of skew lines is the pair of lines through opposite edges of a regular tetrahedron . Lines that are coplanar either intersect or are parallel, so skew lines exist only in three or more dimension s. Explanation If each line in a pair of skew lines is defined by two Point geometry point s, then these four ... of skew lines. Therefore, a test of whether two pairs of points math a , b and math c , d define skew lines is to apply the formula for the volume of a tetrahedron, math 1 V & 124 det a b , b c ... a unit cube , they will almost surely define a pair of skew lines, because after the first three points have been chosen the fourth point will define a non skew line if, and only if, it is coplanar ... will almost certainly turn them into skew lines. In this sense, skew lines are the usual case, and parallel or intersecting lines are special cases. Configurations of multiple skew lines A configuration of skew lines is a set of lines in which all pairs are skew. Two configurations are said to be isotopic ... throughout the transformation the invariant that all pairs of lines remain skew. Any two configurations ... . Skew lines and ruled surfaces If one rotates a line L around another line L skew but not perpendicular ... it also contains a second family of lines that are also skew to L at the same distance as L from it but with the opposite ... families of mutually skew lines. A third type of ruled surface is the hyperbolic paraboloid . Like the hyperboloid of one sheet, the hyperbolic paraboloid has two families of skew lines in each of the two families the lines are parallel to a common plane although not to each other. Any three skew lines ... . Distance between two skew lines To calculate the distance between two skew lines the lines are expressed ... LineDistance title Line Line Distance ref math d mathbf n cdot mathbf c mathbf a math . Skew flats ... more details
A skew heap or self adjusting heap is a heap data structure heap data structure implemented as a binary tree . Skew heaps are advantageous because of their ability to merge more quickly than binary heaps. In contrast with binary heap s, there are no structural constraints, so there is no guarantee that the height of the tree is logarithmic. Only two conditions must be satisfied The general heap order must be enforced Every operation add, remove min, merge on two skew heaps must be done using a special skew heap merge . A skew heap is a self adjusting form of a leftist tree leftist heap which attempts to maintain balance by unconditionally swapping all nodes in the merge path when merging two heaps. The merge operation is also used when adding and removing values. With no structural constraints, it may seem that a skew heap would be horribly inefficient. However, amortized analysis amortized complexity analysis can be used to demonstrate that all operations on a skew heap can be done in O log n . ref http www.cse.yorku.ca andy courses 4101 lecture notes LN5.pdf ref Definition Skew heaps may be described with the following Recursion recursive definition A heap with only one element is a skew heap. The result of skew merging two skew heaps math sh 1 math and math sh 2 math is also a skew heap. Operations Merging two heaps When two skew heaps are to be merged together, we can use a similar process as the merge of two Leftist tree leftist heaps Compare roots of two heaps let p be the heap with the smaller root, and q be the other heap. Let r be the name of the resulting new heap ... Adding values Adding a value to a skew heap is like merging a tree with one node together with the original ... functional languages, skew heaps become extremely simple to implement. Here is a complete sample ... aaw Pourhashemi Animations comparing leftist heaps and skew heaps, York University http people.cis.ksu.edu ... Binary trees Category Heaps data structures th Skew heap ... more details
More footnotes article date August 2011 Skew deviation is an unusual ocular deviation strabismus , wherein the eyes move upward hypertropia , but in opposite directions. Skew deviation is caused by abnormal prenuclear vestibular input to the ocular motor nuclei , most commonly due to brainstem or cerebellar stroke . Other causes include multiple sclerosis and head trauma . Skew deviation is usually characterized by torticollis head tilting and binocular vision binocular Wiktionary torsion . The exact pathophysiology of skew deviation remains incompletely understood. Skew deviation appears to be a perturbation of the ocular tilt reaction , which is itself probably a vestigial righting response used to keep fish and other lateral eyed animals properly oriented. ref cite journal pages 105 28 doi 10.1016 j.survophthal.2005.12.008 title Skew Deviation Revisited year 2006 last1 Brodsky first1 M last2 Donahue first2 S last3 Vaphiades first3 M last4 Brandt first4 T journal Survey of Ophthalmology volume 51 issue 2 pmid 16500212 ref Is poorly understood disorder of gaze in which is maintain vertical deviation of one eye above the other. The patient complains of vertical diplopia. Occurs with lesion of brain stem and cerebellum References reflist Further reading ISBN date August 2011 cite book last1 Adams last2 Victor title Principles of Neurology edition 6 year 1997 Page needed date August 2011 Category Diseases of the eye and adnexa eye stub de Hertwig Magendie Syndrom ... more details
In mathematics , a skew gradient of a harmonic function over a simply connected domain with two real dimensions is a vector field that is everywhere orthogonal to the gradient of the function, and has the same Magnitude mathematics magnitude that the gradient has. Definition The skew gradient can be defined using complex analysis and the Cauchy Riemann equations . Let math f z x,y u x,y iv x,y math be a complex valued analytic function, where u , v are real valued scalar functions of the real variables x , y . A skew gradient is defined as math nabla perp u x,y nabla v x,y math and from the Cauchy Riemann equations , it is derived that math nabla perp u x,y frac partial u partial y , frac partial u partial x math Properties The skew gradient has two interesting properties. It is everywhere orthogonal to the gradient of u, and of the same length math nabla u x,y cdot nabla perp u x,y 0 , rVert nabla u rVert rVert nabla perp u rVert math References Refbegin Peter Olver, http www.math.umn.edu olver pdn.html Introduction to Partial Differential Equations, ch. 7, p. 232 Refend Category Differential calculus Category Generalizations of the derivative Category Linear operators in calculus Category Vector calculus ... more details
A skew arch also known as an oblique arch is a method of construction that enables an arch bridge to span ... that is the plan view of a regular, or square arch . In the case of a masonry skew arch the construction ... to build a skew arch of brick . The problem of building skew arch masonry bridges was addressed .... Buck 1839 and William Froude c. 1844 . Image Sickergill Skew Bridge in 1898.jpg thumb 300px A masonry skew arch bridge photographed shortly after its completion in 1898, showing the helicoidal nature ... Image Store Street Aqueduct.jpg thumb Store Street Aqueduct from Store Street Image Skew Bridge geograph.org.uk 60485.jpg thumb The skew bridge over the river Gaunless Image Denbigh Hall Bridge on the London and Birmingham railway.jpg thumb A contemporary engraving of Denbigh Hall Bridge Skew bridges ... ?id 0u5G8E3uPUAC&pg PA235 ref ref name fox cite journal title On the Construction of Skew Arches ... with a skew angle Cref2 A of 63 and a skew span Cref2 B of convert 42 ft m , resulting in a clear span ... by rival engineers were less successful and for a time skew bridges were considered weak in comparison ... The Analysis of Skew Arches using Shell Theory author Chandler, H. W. coauthor Chandler, C. M. journal ... a solution to the problem of constructing a strong skew arch and as a consequence all his overbridges ... railways, in as straight a line as possible, that rekindled the civil engineer s interest in the skew arch bridge. ref name troyano ref name fox The false skew arch Image Colostbridge b.jpg thumb Colorado Street Bridge, an example of a false skew arch The strength of a regular arch also known ... arch causes them also to lie perpendicular to its faces. For only slightly oblique bridges, where the skew ... is known as a false skew arch and analysis of the forces within it shows that in each corner where ... stream treatiseontheory00cullrich page 30 mode 2up ref An example of such a false skew arch is the Colorado ... built a number of false skew arches, one of them with a skew angle as great as 19 , as accommodation ... more details
Skew is a term used in antenna radio antenna engineering . It is a technique to improve the horizontal radiation pattern of a high power transmitter station . In a high power VHF or UHF station, usually the antenna system is constructed to broadcast to four directions each separated 90 from each other. So the directivity of the antenna system resembles a four leaf clover . While settlements within the main lobe receive enough energy, the energy received by the settlements between the main lobes may be 6 dB less. One popular method to solve the problem is to skew the antenna panels symmetrically around the central axis of the mast. ref R.Busi High altitude VHF and UHF Broadcasting stations , EBU technical center, Brussels, 1967 p 25 ref Usually a skew of 4 gives the desired almost uniform horizontal radiation pattern. But in cases where more than one Radio frequency RF signal is applied to antenna system via combiner , the improvement in the horizontal radiation pattern may be inadequate for some signals. References references Analogue TV transmitter topics Category Antennas radio Category Broadcast engineering ... more details
Skew Peak coor dm 77 13 S 160 42 E is a mountain , 2,535 m, just west of the head of Frazier Glacier , in the Clare Range of Victoria Land . So named in 1957 by the Northern Survey Party of the Commonwealth Trans Antarctic Expedition 1956 58 because the summit is notably asymmetrical from all directions. usgs gazetteer Category Mountains of Victoria Land Category Scott Coast ScottCoast geo stub ... more details
A system of skew coordinates is a coordinate system where the coordinate surfaces are not orthogonal ref http mathworld.wolfram.com SkewCoordinateSystem.html Skew Coordinate System at Mathworld ref , in contrast to orthogonal coordinates . Skew coordinates tend to be more complicated to work with compared to orthogonal coordinates since the metric tensor will have nonzero off diagonal components, preventing many drastic simplifications in formulas for tensor algebra and tensor calculus . The nonzero off diagonal components of the metric tensor are a direct result of the non orthogonality of the basis vectors of the coordinates, since by definition ref name p13 cite book last Lebedev first Leonid P. authorlink coauthors title Tensor Analysis publisher World Scientific date 2003 location pages 13 url doi id isbn 9812383603 ref math g i j mathbf e i cdot mathbf e j math where math g i j math is the metric tensor and math mathbf e i math the covariant basis vector s. These coordinate systems can be useful if the geometry of a problem fits well into a skewed system. For example, solving Laplace s equation in a parallelogram will be easiest when done in appropriately skewed coordinates. Cartesian coordinates with one skewed axis Image SkewCartesianSystem.svg thumb right A Cartesian coordinate system where the x axis has been bent toward the z axis. The simplest 3D case of a skew coordinate system is a Cartesian coordinates Cartesian one where one of the axes say the x axis has been bent by some angle math phi math , staying orthogonal to one of the remaining two axes. For this example, the x axis of a Cartesian coordinate has been bent toward the z axis by math phi math , remaining orthogonal to the y axis. Algebra and useful quantities Let math mathbf e 1 math , math mathbf e 2 math , and math mathbf e 3 math respectively be unit vectors along the math x math , math y math , and math z math axes. These represent the Covariance and contravariance of vectors covariant basis ... more details
In game theory , a symmetric game is a game where the payoffs for playing a particular strategy depend only on the other strategies employed, not on who is playing them. If one can change the identities of the players without changing the payoff to the strategies, then a game is symmetric. Symmetry can come in different varieties. Ordinally symmetric games are games that are symmetric with respect to the ordinal structure of the payoffs. A game is quantitatively symmetric if and only if it is symmetric with respect to the exact payoffs. Symmetry in 2x2 games border 1 align right cellpadding 4 cellspacing 0 style margin 1em 1em 1em 0 background f9f9f9 border 1px aaa solid border collapse collapse font size 95 E F E a, a b, c F c, b d, d Only 12 out the 144 ordinally distinct 2x2 game s are symmetric. However, many of the commonly studied 2x2 games are at least ordinally symmetric. The standard representations of game of chicken chicken , the Prisoner s Dilemma , and the Stag hunt are all symmetric games. Formally, in order for a 2x2 game to be symmetric, its payoff matrix must conform to the schema pictured to the right. The requirements for a game to be ordinally symmetric are weaker, there it need only be the case that the ordinal ranking of the payoffs conform to the schema on the right. Symmetry and equilibria Nash 1951 shows that every symmetric game has a symmetric mixed strategy Nash equilibrium . Cheng et al. 2004 show that every two strategy symmetric game has a not necessarily symmetric pure strategy Nash equilibrium . Uncorrelated asymmetries payoff neutral asymmetries Symmetries here refer to symmetries in payoffs. Biologists often refer to asymmetries in payoffs ... to be symmetric if for any permutation math pi math , math U i a 1, ldots,a i, ldots,a N U pi ... Vorobeychik and Michael P. Wellman. Notes on Equilibria in Symmetric Games, International Joint Conference ... reeves.pdf http www.gametheory.net dictionary Games SymmetricGame.html Symmetric Game at http www.gametheory.net ... more details
In mathematics, the term symmetric product can refer to The Symmetric tensor Symmetric part of a tensor symmetric part of a tensor The symmetric product of an algebraic curve The infinite symmetric product SP X of a space X in algebraic topology disambig ... more details
wiktionary Matrix may refer to TOCright Math and science Matrix mathematics , a rectangular array of numbers, symbols or expressions Matrix biology , the material or tissue between cells in which more specialized structures are embedded Matrix chemical analysis , the non analyte components of a sample Matrix geology , the fine grained material in which larger objects are embedded Harris matrix , an archeological tool Metal matrix , material used in a metal matrix composite Matrix isolation , an experimental technique in chemistry and physics Film and television The Matrix franchise The Matrix franchise , a science fiction franchise The Matrix , the first film in the franchise The Matrix Music from the Motion Picture , a soundtrack album Matrix TV series Matrix TV series Matrix Doctor Who Matrix Doctor Who , a computer system Matrix, a ReBoot character John Matrix, a Commando film Commando character Music and audio Matrix music , an unchanging element of variations Matrix artist , a British DJ Matrix jazz group The Matrix production team M rix , an album by P.A.L. Clave matrix Keyboard matrix circuit Matrix decoder , a technology for converting audio channels Matrix or matrix master , a master disc used in the production of gramophone records Matrix , a song by Chick Corea on the album Now He Sings, Now He Sobs Comics and literature Matrix comics , a DC Comics character Matrix Doctor Who novel Matrix Doctor Who novel , by Robert Perry and Mike Tucker Matrix of Leadership , a Transformers plot element Matrix, a Neuromancer plot element Business and law MATRIX Northern Ireland Science Industry Panel Matrix Business Technologies , a telecommunications firm Matrix Chambers , a barristers set Matrix Games , an American video game publisher founded 1999 Matrix management , an organizational management style Matrix Partners , a private equity investment firm Matrix Software , a Japanese video game developer founded 1994 Growth share matrix , a business analysis technique Transportation ... more details
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