+(* The default of term is the thesis of the goal to be prooved *)
+val unfold_tac:
+ ProofEngineTypes.lazy_term option ->
+ pattern:ProofEngineTypes.pattern ->
+ ProofEngineTypes.tactic
+
+val change_tac:
+ pattern:ProofEngineTypes.pattern ->
+ ProofEngineTypes.lazy_term ->
+ ProofEngineTypes.tactic
+