نتایج جستجو برای: doubly stochastic matrices
تعداد نتایج: 210230 فیلتر نتایج به سال:
To a unitary matrix U we associate a doubly stochastic matrix M by taking the modulus squared of each element of U. To study the connection between onset of quantum chaos on graphs and ergodicity of the underlying Markov chain, specified by M, we study the limiting distribution of the spectral gap of M when U is taken from the Circular Unitary Ensemble and the dimension N of U is taken to infin...
Given an n-vertex graph G, the matrix Ω(G) = (In + L(G))−1 = (ωij) is called the doubly stochastic graph matrix of G, where In is the n × n identity matrix and L(G) is the Laplacian matrix of G. Let ω(G) be the smallest element of Ω(G). Zhang and Wu [X.D. Zhang and J.X. Wu. Doubly stochastic matrices of trees. Appl. Math. Lett., 18:339–343, 2005.] determined the tree T with the minimum ω(T ) am...
We study the calculation of the volume of the polytope Bn of n × n doubly stochastic matrices; that is, the set of real non-negative matrices with all row and column sums equal to one. We describe two methods. The first involves a decomposition of the polytope into simplices. The second involves the enumeration of “magic squares”, i.e., n×n non-negative integer matrices whose rows and columns a...
In the present we introduce a concept of doubly stochastic quadratic operator. We prove necessary and sufficient conditions for doubly stochasticity of operator. Besides, we prove that the set of all doubly stochastic operators forms convex polytope. Finally, we study analogue of Birkhoff’s theorem for the class of doubly stochastic operators. Mathematics Subject Classification: 15A51, 15A63, 4...
In the present note we study the existence or non-existence of doubly warped and doubly twisted product CR-submanifolds in nearly Kaehler manifolds.
We present preliminary results from Fermilab E791 on D 0 ? D 0 mixing and doubly Cabibbo-suppressed decays (DCSD) of the D 0 and D + mesons. The time dependence of the wrong-sign signal (D 0 ! K + ?) is used to establish separate limits on DCSD and mixing. From one third of our data we obtained r mix < 0:47%, r DCSD < 2:7% at the 90% conndence level.
We consider the minimum permanents and minimising matrices on the faces of the polytope of doubly stochastic matrices whose nonzero entries coincide with those of, respectively, Um,n = [ In Jn,m Jm,n 0m ] and Vm,n = [ In Jn,m Jm,n Jm,m ] . We conjecture that Vm,n is cohesive but not barycentric for 1 < n < m + √ m and that it is not cohesive for n > m + √ m. We prove that it is cohesive for 1 <...
Abstract We provide a decomposition that is sufficient in showing when symmetric tridiagonal matrix A A completely positive. Our can be applied to wide range of matrices. give alternate proofs for number related results found the literature simple, straightforward manner. show cp-rank any positive irreducible doubly st...
We provide an explicit combinatorial formula for the volume of the polytope of n× n doubly-stochastic matrices, also known as the Birkhoff polytope. We do this through the description of a generating function for all the lattice points of the closely related polytope of n × n real non-negative matrices with all row and column sums equal to an integer t. We can in fact recover similar formulas f...
Quantum measurements can be interpreted as a generalisation of probability vectors, in which non-negative real numbers are replaced by positive semi-definite operators. We extrapolate this analogy to define doubly stochastic matrices that we call normalised tensors (DNTs), and formulate corresponding version Birkhoff-von Neumann's theorem, states permutations the extremal points set matrices. p...
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