Analyzing the NBER patent database (Hall, Jaffe and Trajtenberg):


## Files

Generally comments are in files but some exceptions:

* missing_patents.txt: list of patent numbers which are in the cite file but
  *not* in the patent file (and so needed to be added in when building the db).
  Originate from code in the file.

## Eigenvalues of Sparse Matrices

In scipy: