Let A be a matrix over the integers, and let p be a positive integer. A submatrix B of A is zerosum mod p if the sum of each row of B and the sum of each column of B is a multiple of p. Let M( p, k) denote the least integer m for which every square matrix of order at least m has a square submatrix o
On sums of three square-zero matrices
โ Scribed by K. Takahashi
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 98 KB
- Volume
- 306
- Category
- Article
- ISSN
- 0024-3795
No coin nor oath required. For personal study only.
โฆ Synopsis
Wang and Wu characterized matrices which are sums of two square-zero matrices, and proved that every matrix with trace-zero is a sum of four square-zero matrices. Moreover, they gave necessary or sufficient conditions for a matrix to be a sum of three square-zero matrices. In particular, they proved that if an n ร n matrix A is a sum of three square-zero matrices, the dim ker(A -ฮฑI ) 3n/4 for any scalar ฮฑ / = 0. Proposition 1 shows that this condition is not necessarily sufficient for the matrix A to be a sum of three square-zero matrices, and characterizes sums of three square-zero matrices among matrices with minimal polynomials of degree 2.
๐ SIMILAR VOLUMES
## Abstract For a graph __G__ whose number of edges is divisible by __k__, let __R__(__G,Z__~k~) denote the minimum integer __r__ such that for every function __f__: __E__(__K__~r~) โฆ __Z__~k~ there is a copy __G__^1^ of __G__ in __K__~r~ so that ฮฃeโ__E__(__G__^1^) __f(e)__ = 0 (in __Z__~k~). We pr