This paper is a chronological survey, with no proofs, of a direction in categorical algebra, which is based on categorical Galois theory and involves generalized central extensions, commutators, and internal groupoids in Barr exact Mal’tsev and more general categories. Galois theory proposes a notion of central extension, and motivates the study of internal groupoids, which is then used as an a...

The Zagros orogeny in Iran is associated with two successive geodynamic events during the Tertiary period, a Paleogene NE-directed regional crustal extension followed by a Miocene NW-directed regional crustal extension and a magmatic flare-up. The current study was undertaken to reanalyze previous structural work developed on the extensional Chapedony metamorphic core complex in Central Iran ex...

this paper is a chronological survey, with no proofs, of a direction in categorical algebra, which is based on categorical galois theory and involves generalized central extensions, commutators, and internal groupoids in barr exact mal’tsev and more general categories. galois theory proposes a notion of central extension, and motivates the study of internal groupoids, which is then used as an a...

We introduce super Yangian double DYh̄[gl(m|n)] and its central extension ̂ DYh̄[gl(m|n)]. We give their defining relations in terms of current generators and obtain Drinfeld comultiplication. Queen Elizabeth II Fellow; Email: [email protected] This paper concerns with Drinfeld current realization [1] of super Yangian double DYh̄[gl(m|n)] and its central extension ̂ DYh̄[gl(m|n)]. The Yangian doubl...