Aspects of Feynman Graphs

Points (vertices) and lines (edges) can be compared to the particles and waves in nature. Graphical, visual representations of objects and processes possess many properties which are quite advantageous and practically useful. Richard P. Feynman, made copious applications of the graph-theoretic language, ideas and methods for understanding the micro-world of elementary particles and their interactions. Here, we discus certain significant features of Feynman graphs or diagrams in the modern context. We make a novel observation that the CPT theorem is embedded in the space-time concepts of Feynman graphs and hence the success and precision of some the calculations of QED are in fact testament to the correctness and accuracy of this theorem.