The theory of abelian categories proved very useful, providing an ax-iomatic framework for homology and cohomology of modules over a ring (in particular, abelian groups) [5]. A similar framework has been lacking for non-abelian (co)homology, the subject of which includes the categories of groups and Lie algebras etc. The point of my thesis is that semi-abelian categories (in the sense of Janeli...

the present paper sets out to investigate the syntactic category of persian modals, šâyad ‘perhaps’ and bâyad ‘must’. the syntactic category of the two modal elements has been viewed differently by different scholars. a number of scholars argue that both šâyad and bâyad are modal auxiliaries, while others claim that they both are modal adverbs. we propose that šâyad is a modal adverb and bâyad ...

Schanuel has pointed out that there are mathematically interesting categories whose relationship to the ring of integers is analogous to the relationship between the category of finite sets and the semi-ring of non-negative integers. Such categories are inherently geometrical or topological, in that the mapping to the ring of integers is a variant of Euler characteristic. In these notes, I sket...