Green index and finiteness conditions for semigroups

On Finite Generation and Other Finiteness Conditions for Wreath Products of Semigroups

Finiteness Conditions for Strictness Analysis

We give upper bounds on the number of times the fixed point operator needs to be unfolded for strictness analysis of functional languages with lists. This extends previous work both in the syntax-directed nature of the approach and in the ability to deal with Wadler’s method for analysing lists. Limitations of the method are indicated.

The finiteness problem for automaton semigroups is undecidable

The finiteness problem for automaton groups and semigroups has been widely studied, several partial positive results are known. However we prove that, in the most general case, the problem is undecidable. We study the case of automaton semigroups. Given a NW-deterministic Wang tile set, we construct a Mealy automaton, such that the plane admits a valid Wang tiling if and only if the Mealy autom...

Correspondence Functors and Finiteness Conditions

We investigate the representation theory of finite sets. The correspondence functors are the functors from the category of finite sets and correspondences to the category of k-modules, where k is a commutative ring. They have various specific properties which do not hold for other types of functors. In particular, if k is a field and if F is a correspondence functor, then F is finitely generate...

Finiteness Conditions for Light-Front Hamiltonians

Many advantages of the light-front (LF) formulation for bound state problems arise from the manifest boost invariance in the longitudinal direction [1{5]. The price for this advantage is that other symmetries, such as parity or rotational invariance (for rotations around a transverse axis) are no longer manifest [6,7]. From the technical point of view, the loss of manifest parity and full rotat...