-lemma vpushs_inv_fold (M): is_model M →
- ∀L,T1,T2,gv,lv. ⟦L+T1⟧[gv, lv] ≗{M} ⟦L+T2⟧[gv, lv] →
- ∀v. L ⨁[gv] lv ≘ v → ⟦T1⟧[gv, v] ≗ ⟦T2⟧[gv, v].
-#M #HM #L elim L -L [| #K * [| * ]]
+lemma vpushs_inv_fold (M): is_model M → is_injective M →
+ ∀L,T1,T2,gv,lv. ⟦L+T1⟧[gv, lv] ≗{M} ⟦L+T2⟧[gv, lv] →
+ ∀v. L ⨁[gv] lv ≘ v → ⟦T1⟧[gv, v] ≗ ⟦T2⟧[gv, v].
+#M #H1M #H2M #L elim L -L [| #K * [| * ]]