François Truffaut l’a montré à de multiples reprises : il est l’un des grands épistoliers la seconde moitié du xxe siècle. Par masse lettres écrites — plusieurs milliers, par jour l’adolescence mort —, leur variété, diversité personnes auxquelles s’adressait. Et l’inégalable pouvoir qu’il conférait une puissance séduction, conviction, confession, d’information et polémique, portée, selon tous c...

A subgroup H of a group G is called ss-quasinormal in G if there is a subgroup B of G such that G = HB and H permutes with every Sylow subgroup of B; H is called weakly s-permutable in G if there is a subnormal subgroup T of G such that G = HT and H ∩ T ≤ HsG, where HsG is the subgroup of H generated by all those subgroups of H which are s-permutable in G. We fix in every non-cyclic Sylow subgr...

After discussing some basic facts about generalized module maps, we use the representation theory of the algebra Ba(E) of adjointable operators on a Hilbert B–module E to show that the quotient of the group of generalized unitaries on E and its normal subgroup of unitaries on E is a subgroup of the group of automorphisms of the range ideal BE of E in B. We determine the kernel of the canonical ...