unique tips: add to list of invariants

diff --git a/invariants.tex b/invariants.tex
index 20d6e7644f76148d3c9790b31b55a47e8489fa35..bc3813e6b83593e5d5ad0ad9c2b59c9a0f53d000 100644 (file)
--- a/invariants.tex
+++ b/invariants.tex
@@ -18,6 +18,9 @@ We maintain these each time we construct a new commit. \\
 \[\eqn{Coherence:}{
   \bigforall_{C,\p} C \haspatch \p \lor C \nothaspatch \p
 }\]
 \[\eqn{Coherence:}{
   \bigforall_{C,\p} C \haspatch \p \lor C \nothaspatch \p
 }\]

+\[\eqn{Unique Tips:}{
+  \bigforall_{C,\p} C \haspatch \p \implies \pendsof{C}{\p} = \{ T \}
+}\]

 \[\eqn{Foreign Inclusion:}{
   \bigforall_{D \text{ s.t. } \patchof{D} = \bot} D \isin C \equiv D \leq C
 }\]
 \[\eqn{Foreign Inclusion:}{
   \bigforall_{D \text{ s.t. } \patchof{D} = \bot} D \isin C \equiv D \leq C
 }\]