= Finite presentation from a synchronous combing
Attach <relators> for every identity word of length at most $2K+2$, where $K$ is an integer fellow-traveller constant. For any null loop, connect its consecutive <combing> <paths> at integer heights by rungs of length at most $K$. Each resulting quadrilateral has perimeter at most $2K+2$ and thus is a <relator>. The bottom row is collapsed at the identity and the top row is the original loop, so these finitely many <relators> fill every null word and present the group.
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