Feynman's Operational Calculus and Beyond

This book is aimed at providing a coherent, essentially self-contained, rigorous and comprehensive abstract theory of Feynman''s operational calculus for noncommuting operators. Although it is inspired by Feynman''s original heuristic suggestions and time-ordering rules in his seminal 1951 paper An operator calculus having applications in quantum electrodynamics, as will be made abundantly clear i...