2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/162229A new class of coefficients for the Hopf-cyclic homology of module algebras and coalgebras is introduced. These coefficients, termed stable anti-Yetter-Drinfeld contramodules, are both modules and contramodules of a Hopf algebra that satisfy certain compatibility conditions.8 pages; misprints in the definition of t_n and calculations involving t_n on page 4 are correctedK-Theory and Homology19D55; 16W30text