Butterflies in a semi-abelian context

Monitoring of butterflies within a landscape context

Monitoring of butterflies is most often only directed towards the grassland fauna. Species associated with other vegetation types, as well as the impact of the surrounding landscape, often become neglected. The aim with this study was, in contrast, to perform a novel landscape-based monitoring method for butterflies in diverse vegetation types and more specifically (i) evaluate the impact of en...

Relative Semi-abelian Categories

We introduce a relative semi-abelian category as a pair (C,E), where C is a pointed category with finite limits, and E is a class of normal epimorphisms in C satisfying certain conditions, stronger than those defining a relative homological category [2]. In the absolute case, i.e. when E is the class of all regular epimorphisms in C, the pair (C,E) is relative semi-abelian if and only if C is s...

Semi-abelian Exact Completions

The theory of protomodular categories provides a simple and general context in which the basic theorems needed in homological algebra of groups, rings, Lie algebras and other non-abelian structures can be proved [2] [3] [4] [5] [6] [7] [9] [20]. An interesting aspect of the theory comes from the fact that there is a natural intrinsic notion of normal monomorphism [4]. Since any internal reflexi...

Semi-complete Primary Abelian Groups1

Semi-abelian Categories and Exactness

We show that every semi-abelian category, as defined by Palamodov, possesses a maximal exact structure in the sense of Quillen and that the exact structure of a quasi-abelian category is a special case thereof.