- #A; napply mk_binary_morphism1
- [ napply (λS,S': qpowerclass_setoid ?. S ⊆ S')
- | #a; #a'; #b; #b'; *; #Ha1; #Ha2; *; #Hb1; #Hb2; napply mk_iff; #H
- [ napply (subseteq_trans … a' a) (* anche qui, perche' serve a'? *)
- [ nassumption | napply (subseteq_trans … a b); nassumption ]
- ##| napply (subseteq_trans … a a') (* anche qui, perche' serve a'? *)
- [ nassumption | napply (subseteq_trans … a' b'); nassumption ] ##]
+ #A; @
+ [ napply (λS,S'. S ⊆ S')
+ | #a; #a'; #b; #b'; *; #Ha1; #Ha2; *; #Hb1; #Hb2; @; #H
+ [ napply (subseteq_trans … a)
+ [ nassumption | napply (subseteq_trans … b); nassumption ]
+ ##| napply (subseteq_trans … a')
+ [ nassumption | napply (subseteq_trans … b'); nassumption ] ##]
+nqed.
+
+unification hint 0 ≔ A,a,a'
+ (*-----------------------------------------------------------------*) ⊢
+ eq_rel ? (eq A) a a' ≡ eq_rel1 ? (eq1 (setoid1_of_setoid A)) a a'.
+
+nlemma intersect_ok: ∀A. 𝛀^A → 𝛀^A → 𝛀^A.
+ #A; #S; #S'; @ (S ∩ S');
+ #a; #a'; #Ha; @; *; #H1; #H2; @
+ [##1,2: napply (. Ha^-1‡#); nassumption;
+##|##3,4: napply (. Ha‡#); nassumption]
+nqed.
+
+alias symbol "hint_decl" = "hint_decl_Type1".
+unification hint 1 ≔
+ A : setoid, B,C : qpowerclass A ⊢
+ pc A (mk_qpowerclass ? (B ∩ C) (mem_ok' ? (intersect_ok ? B C)))
+ ≡ intersect ? (pc ? B) (pc ? C).
+
+nlemma intersect_ok': ∀A. binary_morphism1 (powerclass_setoid A) (powerclass_setoid A) (powerclass_setoid A).
+ #A; @ (λS,S'. S ∩ S');
+ #a; #a'; #b; #b'; *; #Ha1; #Ha2; *; #Hb1; #Hb2; @; #x; nnormalize; *; #Ka; #Kb; @
+ [ napply Ha1; nassumption
+ | napply Hb1; nassumption
+ | napply Ha2; nassumption
+ | napply Hb2; nassumption]