theorem lreq_canc_dx: ∀f. right_cancellable … (lreq f).
/3 width=3 by lexs_canc_dx, lreq_trans, lreq_sym/ qed-.
-theorem lreq_join: ∀L1,L2,f1. L1 ≡[f1] L2 → ∀f2. L1 ≡[f2] L2 →
+theorem lreq_join: ∀f1,L1,L2. L1 ≡[f1] L2 → ∀f2. L1 ≡[f2] L2 →
∀f. f1 ⋓ f2 ≡ f → L1 ≡[f] L2.
/2 width=5 by lexs_join/ qed-.
-theorem lreq_meet: ∀L1,L2,f1. L1 ≡[f1] L2 → ∀f2. L1 ≡[f2] L2 →
+theorem lreq_meet: ∀f1,L1,L2. L1 ≡[f1] L2 → ∀f2. L1 ≡[f2] L2 →
∀f. f1 ⋒ f2 ≡ f → L1 ≡[f] L2.
/2 width=5 by lexs_meet/ qed-.