--- /dev/null
+Require pr2_confluence.
+Require pr3_defs.
+
+ Section pr3_confluence. (*************************************************)
+
+(*#* #caption "confluence with single step reduction: strip lemma" *)
+(*#* #cap #cap c, t0, t1, t2, t *)
+
+ Theorem pr3_strip : (c:?; t0,t1:?) (pr3 c t0 t1) -> (t2:?) (pr2 c t0 t2) ->
+ (EX t | (pr3 c t1 t) & (pr3 c t2 t)).
+
+(*#* #stop proof *)
+
+ Intros until 1; XElim H; Intros.
+(* case 1 : pr3_r *)
+ XEAuto.
+(* case 2 : pr3_u *)
+ Pr2Confluence.
+ LApply (H1 x); [ Clear H1 H2; Intros H1 | XAuto ].
+ XElim H1; Intros; XEAuto.
+ Qed.
+
+(*#* #start proof *)
+
+(*#* #caption "confluence with itself: Church-Rosser property" *)
+(*#* #cap #cap c, t0, t1, t2, t *)
+
+ Theorem pr3_confluence : (c:?; t0,t1:?) (pr3 c t0 t1) -> (t2:?) (pr3 c t0 t2) ->
+ (EX t | (pr3 c t1 t) & (pr3 c t2 t)).
+
+(*#* #stop file *)
+
+ Intros until 1; XElim H; Intros.
+(* case 1 : pr3_r *)
+ XEAuto.
+(* case 2 : pr3_u *)
+ LApply (pr3_strip c t3 t5); [ Clear H2; Intros H2 | XAuto ].
+ LApply (H2 t2); [ Clear H H2; Intros H | XAuto ].
+ XElim H; Intros.
+ LApply (H1 x); [ Clear H1 H2; Intros H1 | XAuto ].
+ XElim H1; Intros; XEAuto.
+ Qed.
+
+ End pr3_confluence.
+
+ Tactic Definition Pr3Confluence :=
+ Match Context With
+ | [ H1: (pr3 ?1 ?2 ?3); H2: (pr2 ?1 ?2 ?4) |-? ] ->
+ LApply (pr3_strip ?1 ?2 ?3); [ Clear H1; Intros H1 | XAuto ];
+ LApply (H1 ?4); [ Clear H1 H2; Intros H1 | XAuto ];
+ XElim H1; Intros
+ | [ H1: (pr3 ?1 ?2 ?3); H2: (pr3 ?1 ?2 ?4) |-? ] ->
+ LApply (pr3_confluence ?1 ?2 ?3); [ Clear H1; Intros H1 | XAuto ];
+ LApply (H1 ?4); [ Clear H1 H2; Intros H1 | XAuto ];
+ XElim H1; Intros
+ | _ -> Pr2Confluence.
+
+(*#* #start file *)
+
+(*#* #single *)