## Stem hopf$ (all stems)

### 2 papers:

- RTA-2015-Hellstrom #algebra #network
- Network Rewriting II: Bi- and Hopf Algebras (LH), pp. 194–208.
- ICALP-1988-MehlhornY #how #theorem
- Constructive Hopf’s Theorem: Or How to Untangle Closed Planar Curves (KM, CKY), pp. 410–423.