Positivity and matrix semigroups

Function spaces of Rees matrix semigroups

We characterize function spaces of Rees matrixsemigroups. Then we study these spaces by using the topologicaltensor product technique.

Mortality in Matrix Semigroups

We present a new shorter and simplified proof for the undecidability of the mortality problem in matrix semigroups, originally proved by Paterson in 1970. We use the clever coding technique introduced by Paterson to achieve also a new result, the undecidability of the vanishing (left) upper corner. Since our proof for the undecidability of the mortality problem uses only 8 matrices, a new bound...

Automatic Rees Matrix Semigroups

We consider the preservation of the properties of automaticity and prefix-automaticity in Rees matrix semigroups over semigroupoids and small categories. Some of our results are new or improve upon existing results in the single-object case of Rees matrix semigroups over semigroups.

The modulus of matrix semigroups

We treat a result concerning the generator of the modulus semigroup of a strongly continuous semigroup acting on the product of Banach lattices with order continuous norm. MCS 2000: 47D06, 47B60

Multiplicative diagonals of matrix semigroups