RT Journal Article T1 Non-formal co-symplectic manifolds A1 Bazzoni, G. A1 Fernández, Marisa A1 Muñoz, Vicente AB We study the formality of the mapping torus of an orientation-preserving diffeomorphism of a manifold. In particular, we give conditions under which a mapping torus has a non-zero Massey product. As an application we prove that there are non-formal compact co-symplectic manifolds of dimension m and with first Betti number b if and only if m = 3 and b >= 2, or m >= 5 and b >= 1. Explicit examples for each one of these cases are given. PB American Mathematical Society SN 0002-9947 YR 2015 FD 2015 LK https://hdl.handle.net/20.500.14352/34631 UL https://hdl.handle.net/20.500.14352/34631 LA eng NO MICINN (Spain) NO UPV/EHU DS Docta Complutense RD 19 abr 2025