At the end of the first paragraph there's an xref to Proposition 4.5.1. Click to open the knowl. Then scroll down to the bottom of the knowl. This has three proofs (for different substatements withing the proposition).
The styling for the three links to open the proof knowls is inconsistent. (But no such issue if you click "in-context" and go to the actual proposition.)
Report from Jeremy Sylvestre email...
Small styling issue:
Go to https://sites.ualberta.ca/~jsylvest/books/DLA1/section-inverses-theory.html
At the end of the first paragraph there's an xref to Proposition 4.5.1. Click to open the knowl. Then scroll down to the bottom of the knowl. This has three proofs (for different substatements withing the proposition).
The styling for the three links to open the proof knowls is inconsistent. (But no such issue if you click "in-context" and go to the actual proposition.)