BRS “Symmetry”, the main role of Raymond Stora

Abstract

We discuss how Raymond Stora's absolute need of mathematical rigor has determined the discovery of BRS “Symmetry”. This need having been the essential reason for the construction of the identity which has been presented by Rouet and Stora in the lectures given at Lausanne-1973. Once written this identity the celebrated discovery has been a matter of reading. We also recall the less celebrated discovery of BRS cohomology and its impact on Physics.