2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/82828We discuss various properties of singlet S pairing in neutron and nuclear matter in terms of the bare nuclon-nucleon interaction. Relations to the NN phase shifts are discussed, as well as various properties of the BCS wave function and the coherence length for fermion superfluids in infinite matter.7 pages, 3 figures included, Revtex style. Proceedings of Condensed Matter Theories 21, Luso, Portugal, 21-27 sept 1997. To appear in Condensed Matter Theories Vol. 13Nuclear Theorytext