Feynman diagrams

Feynman diagrams form a type into which permissible Wick contractions embed.

A permissible Wick contraction is one which does not contribute zero to the vacuum expection value.

Feynman diagrams are based on multisets of FieldOp. This should be contrasted with Wick contractions which are based on lists of FieldOp.

In particular a Feynman diagram is a partion of a Multiset into disjoint pairs.

Note

This directory is currently a work in progress. (Contact JTS before working in this directory.)