merge any Topbloke-controlled branch into any plain git branch.
Given those conditions, Tip Merge and Merge Acyclic do not apply.
-And by Foreign Contents for (wlog) Y, $\forall_{\p, D \in \py} D \not\le Y$
-so then by No Replay $D \not\isin Y$
-so $\neg [ Y \haspatch \p ]$ so neither
-Merge Ends condition applies.
+By Foreign Contents of $L$, $\patchof{M} = \bot$ as well.
+So by Foreign Contents for any $A \in \{L,M,R\}$,
+$\forall_{\p, D \in \py} D \not\le A$
+so by No Replay for A $D \not\isin A$.
+Thus $\pendsof{A}{\py} = \{ \}$ and the RHS of both Merge Ends
+conditions are satisifed.
So a plain git merge of non-Topbloke branches meets the conditions and
is therefore consistent with our model.