Intrinsic reflections and strongly rigid Coxeter groups

It is possible for a group W that is abstractly isomorphic to a Coxeter group to have more than one conjugacy class of Coxeter generating sets, and if S and R are two non-conjugate Coxeter generating sets then it may or may not be the case that some element s ∈ S is conjugate to an element r ∈ R . In this paper we classify the so-called intrinsic reflections: those elements of W whose conjugacy class intersects non-trivially every Coxeter generating set. In combination with previously known results, this leads us to a classification of Coxeter groups for which all Coxeter generating sets are conjugate.