The following preprint is available, in pdf: M. Grandis Coherence and distributive lattices in homological algebra Dip. Mat. Univ. Genova, Preprint 595 (2012) http://www.dima.unige.it/~grandis/Lat.pdf Abstract. Complex systems in homological algebra present problems of coherence that can be solved by proving the distributivity of the sublattices of subobjects generated by the system. The main applications deal with spectral sequences, but the goal of this paper is to convey the importance of distributive lattices (of subobjects) in homological algebra, to researchers outside of this field; a parallel role played by orthodox semigroups (of endorelations) is referred to but not developed here. (This article develops part of a conference at CatAlg2011, Gargnano (Italy), in September 2011.) With best wishes Marco Grandis Dipartimento di Matematica Università di Genova Via Dodecaneso, 35 16146 Genova Italy e-mail: grandis@dima.unige.it tel: +39 010 353 6805 http://www.dima.unige.it/~grandis/ [For admin and other information see: http://www.mta.ca/~cat-dist/ ]