Aperiodic words on three symbols. III.
As shown by Telgársky and Scheepers, winning strategies in the Menger game characterize -compactness amongst metrizable spaces. This is improved by showing that winning Markov strategies in the Menger game characterize -compactness amongst regular spaces, and that winning strategies may be improved to winning Markov strategies in second-countable spaces. An investigation of 2-Markov strategies introduces a new topological property between -compact and Menger spaces.
Under some very strong set-theoretic hypotheses, hereditarily normal spaces (also referred to as T₅ spaces) that are locally compact and hereditarily collectionwise Hausdorff can have a highly simplified structure. This paper gives a structure theorem (Theorem 1) that applies to all such ω₁-compact spaces and another (Theorem 4) to all such spaces of Lindelöf number ≤ ℵ₁. It also introduces an axiom (Axiom F) on crowding of functions, with consequences (Theorem 3) for the crowding of countably compact...
Étant donné l'importance que prennent les grammaires catégorielles dans le domaine de la linguistique computationnelle, il nous a semblé intéressant de dresser un panorama sur cette question. Nous espérons fournir, aux chercheurs intéressés, un matériau de base susceptible de les aider à approfondir par eux-mêmes le sujet.