The maximum distance between two-dimensional Banach spaces.
The structure of linear operators strongly preserving majorizations of matrices.
The structure of linear preservers of left matrix majorization on .
There is no analog of the transpose map for infinite matrices.
In this note we show that there are no ring anti-isomorphism between row finite matrix rings. As a consequence we show that row finite and column finite matrix rings cannot be either isomorphic or Morita equivalent rings. We also show that antiisomorphisms between endomorphism rings of infinitely generated projective modules may exist.
Von der Zerlegung der Discriminante der cubischen Gleichung, welche die Hauptaxen einer Fläche zweiter Ordnung bestimmen, in eine Summe von Quadraten.
Zaměnitelnost endomorfismů lineárních prostorů
Zero-term rank preservers of integer matrices
The zero-term rank of a matrix is the minimum number of lines (row or columns) needed to cover all the zero entries of the given matrix. We characterize the linear operators that preserve the zero-term rank of the m × n integer matrices. That is, a linear operator T preserves the zero-term rank if and only if it has the form T(A)=P(A ∘ B)Q, where P, Q are permutation matrices and A ∘ B is the Schur product with B whose entries are all nonzero integers.
Zero-term ranks of real matrices and their preservers
Zero-term rank of a matrix is the minimum number of lines (rows or columns) needed to cover all the zero entries of the given matrix. We characterize the linear operators that preserve zero-term rank of the real matrices. We also obtain combinatorial equivalent condition for the zero-term rank of a real matrix.
О нильпотентных матрицах
Об отображениях псевдоевклидовых пространств, сохраняющих изотропность векторов.
Структура гиперинвариантных подпространств вещественного конечномерного оператора
Характеристические свойства преобразований Лоренца