Created almost 4 years ago, updated 4 months ago
see Leggett's writings
## [fermions non-conservation in models of particle physics](https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=e9a5a89c6853c281181d4509ef18bec489007258) ## NOT in superconductivity!!! see Leggett's writingsCopy