17 Fevereiro 1997, 14:30
Jírí Adámek, Technical University of Braunschweig
Duality theory for varieties and quasivarieties of algebras

With each variety V of algebras we associate a theory Th(V), which is the dual of the subcategory of all retracts of V-free algebras on finitely many generators. This gives a duality between the category of all varieties and that of all Cauchy-complete small categories with finite products. We further describe a duality betweeen the category of all quasivarieties and the category of small lex categories with enough regular projectives.

These results are joint work with H.-E. Porst and J.Rosicky.