2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/59198We show that semi-infinite cohomology of a finite dimensional graded algebra (satisfying some additional requirements) are a particular case of a general categorical construction. The motivating example is provided by small quantum groups at a root of unity.8 pages. Some expositional changes made; few remarks added, one of them concerning semi-infinite cohomology of small quantum groupsRepresentation TheoryAlgebraic GeometryK-Theory and HomologyQuantum Algebratext