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Stabilizers for nondegenerate matrices of boundary format and Steiner bundles.

Carla Dionisi (2004)

Revista Matemática Complutense

In this paper nondegenerate multidimensional matrices of boundary format in V0 ⊗ ... ⊗ Vp are investigated by their link with Steiner vector bundles on product of projective spaces. For any nondegenerate matrix A the stabilizer for the SL(V0) x ... x SL(Vp)-action, Stab(A), is completely described. In particular we prove that there exists an explicit action of SL(2) on V0 ⊗ ... ⊗ Vp such that Stab(A)0 ⊆ SL(2) and the equality holds if and only if A belongs to a unique SL(V0) x ... x SL(Vp)-orbit...

Stable vector bundles over cuspidal cubics

Lesya Bodnarchuk, Yuriy Drozd (2003)

Open Mathematics

We give a complete classification of stable vector bundles over a cuspidal cubic and calculate their cohomologies. The technique of matrix problems is used, similar to [2, 3].

Steiner forms

Jan Hora (2016)

Commentationes Mathematicae Universitatis Carolinae

A trilinear alternating form on dimension n can be defined based on a Steiner triple system of order n . We prove some basic properties of these forms and using the radical polynomial we show that for dimensions up to 15 nonisomorphic Steiner triple systems provide nonequivalent forms over G F ( 2 ) . Finally, we prove that Steiner triple systems of order n with different number of subsystems of order ( n - 1 ) / 2 yield nonequivalent forms over G F ( 2 ) .

Strict spectral approximation of a matrix and some related problems

Krystyna Ziętak (1997)

Applicationes Mathematicae

We show how the strict spectral approximation can be used to obtain characterizations and properties of solutions of some problems in the linear space of matrices. Namely, we deal with (i) approximation problems with singular values preserving functions, (ii) the Moore-Penrose generalized inverse. Some properties of approximation by positive semi-definite matrices are commented.

Strong 𝐗 -robustness of interval max-min matrices

Helena Myšková, Ján Plavka (2021)

Kybernetika

In max-min algebra the standard pair of operations plus and times is replaced by the pair of operations maximum and minimum, respectively. A max-min matrix A is called strongly robust if the orbit x , A x , A 2 x , reaches the greatest eigenvector with any starting vector. We study a special type of the strong robustness called the strong X-robustness, the case that a starting vector is limited by a lower bound vector and an upper bound vector. The equivalent condition for the strong X-robustness is introduced...

Structure fractals and para-quaternionic geometry

Julian Ławrynowicz, Massimo Vaccaro (2011)

Annales UMCS, Mathematica

It is well known that starting with real structure, the Cayley-Dickson process gives complex, quaternionic, and octonionic (Cayley) structures related to the Adolf Hurwitz composition formula for dimensions p = 2, 4 and 8, respectively, but the procedure fails for p = 16 in the sense that the composition formula involves no more a triple of quadratic forms of the same dimension; the other two dimensions are n = 27. Instead, Ławrynowicz and Suzuki (2001) have considered graded fractal bundles of...

Structure of unitary groups over finite group rings and its application

Jizhu Nan, Yufang Qin (2010)

Czechoslovak Mathematical Journal

In this paper, we determine all the normal forms of Hermitian matrices over finite group rings R = F q 2 G , where q = p α , G is a commutative p -group with order p β . Furthermore, using the normal forms of Hermitian matrices, we study the structure of unitary group over R through investigating its BN-pair and order. As an application, we construct a Cartesian authentication code and compute its size parameters.

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