[ apply (λa,b: form o.{c | BPext o c ⊆ BPext o a ∩ BPext o b });
intros; simplify; apply (.= (†e)‡#); apply refl1
| intros; split; simplify; intros;
- [ apply (. #‡((†e)‡(†e1))); assumption
- | apply (. #‡((†e\sup -1)‡(†e1\sup -1))); assumption]]
+ [ apply (. #‡((†e^-1)‡(†e1^-1))); assumption
+ | apply (. #‡((†e)‡(†e1))); assumption]]
qed.
interpretation "fintersects" 'fintersects U V = (fun21 ___ (fintersects _) U V).
[ apply (λo: basic_pair.λa,b: Ω \sup (form o).{c | BPext o c ⊆ BPextS o a ∩ BPextS o b });
intros; simplify; apply (.= (†e)‡#); apply refl1
| intros; split; simplify; intros;
- [ apply (. #‡((†e)‡(†e1))); assumption
- | apply (. #‡((†e\sup -1)‡(†e1\sup -1))); assumption]]
+ [ apply (. #‡((†e^-1)‡(†e1^-1))); assumption
+ | apply (. #‡((†e)‡(†e1))); assumption]]
qed.
interpretation "fintersectsS" 'fintersects U V = (fun21 ___ (fintersectsS _) U V).
intros (o); constructor 1;
[ apply (λx:concr o.λS: Ω \sup (form o).∃y:carr (form o).y ∈ S ∧ x ⊩ y);
| intros; split; intros; cases e2; exists [1,3: apply w]
- [ apply (. (#‡e1)‡(e‡#)); assumption
- | apply (. (#‡e1 \sup -1)‡(e \sup -1‡#)); assumption]]
+ [ apply (. (#‡e1^-1)‡(e^-1‡#)); assumption
+ | apply (. (#‡e1)‡(e‡#)); assumption]]
qed.
interpretation "basic pair relation for subsets" 'Vdash2 x y = (fun21 (concr _) __ (relS _) x y).