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On the maximal subgroup of the sandwich semigroup of generalized circulant Boolean matrices

Jinsong Chen, Yi Jia Tan (2006)

Czechoslovak Mathematical Journal

Let n be a positive integer, and C n ( r ) the set of all n × n r -circulant matrices over the Boolean algebra B = { 0 , 1 } , G n = r = 0 n - 1 C n ( r ) . For any fixed r -circulant matrix C ( C 0 ) in G n , we define an operation “ * ” in G n as follows: A * B = A C B for any A , B in G n , where A C B is the usual product of Boolean matrices. Then ( G n , * ) is a semigroup. We denote this semigroup by G n ( C ) and call it the sandwich semigroup of generalized circulant...

Perimeter preserver of matrices over semifields

Seok-Zun Song, Kyung-Tae Kang, Young Bae Jun (2006)

Czechoslovak Mathematical Journal

For a rank- 1 matrix A = 𝐚 𝐛 t , we define the perimeter of A as the number of nonzero entries in both 𝐚 and 𝐛 . We characterize the linear operators which preserve the rank and perimeter of rank- 1 matrices over semifields. That is, a linear operator T preserves the rank and perimeter of rank- 1 matrices over semifields if and only if it has the form T ( A ) = U A V , or T ( A ) = U A t V with some invertible matrices U and V.

Power indices of trace zero symmetric Boolean matrices

Bo Zhou (2004)

Discussiones Mathematicae - General Algebra and Applications

The power index of a square Boolean matrix A is the least integer d such that Ad is a linear combination of previous nonnegative powers of A. We determine the maximum power indices for the class of n×n primitive symmetric Boolean matrices of trace zero, the class of n×n irreducible nonprimitive symmetric Boolean matrices, and the class of n×n reducible symmetric Boolean matrices of trace zero, and characterize the extreme matrices respectively.

Rank and perimeter preserver of rank-1 matrices over max algebra

Seok-Zun Song, Kyung-Tae Kang (2003)

Discussiones Mathematicae - General Algebra and Applications

For a rank-1 matrix A = a b t over max algebra, we define the perimeter of A as the number of nonzero entries in both a and b. We characterize the linear operators which preserve the rank and perimeter of rank-1 matrices over max algebra. That is, a linear operator T preserves the rank and perimeter of rank-1 matrices if and only if it has the form T(A) = U ⊗ A ⊗ V, or T ( A ) = U A t V with some monomial matrices U and V.

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