With Gianni Morchio at the Interface Between Mathematics and Physics

We consider a sesquilinear form on sections of a Hermitian bundle over a (not neceI met Gianni Morchio around 1994 in Pisa. My collaborator Krzysztof P. Wojciechowski and I came to work with him and Franco Strocchi on a fascinating problem, the invariance of the Fermi determinant under global chiral transformations. Gianni posessed a rich mathematical culture. He had a very particular way of combining factual thinking with far reaching scientific aims and visions. That and his generosity and friendliness impressed everybody. We became friends, also on the family level, and met again and again for the rest of his life.