-(* Note: apparently this was missing in basic_1 *)
-theorem ssta_mono: ∀h,g,L,T,U1,l1. ⦃h, L⦄ ⊢ T •[g] ⦃l1, U1⦄ →
- ∀U2,l2. ⦃h, L⦄ ⊢ T •[g] ⦃l2, U2⦄ → l1 = l2 ∧ U1 = U2.
-#h #g #L #T #U1 #l1 #H elim H -L -T -U1 -l1
-[ #L #k #l #Hkl #X #l2 #H
- elim (ssta_inv_sort1 … H) -H #Hkl2 #H destruct
- >(deg_mono … Hkl2 … Hkl) -g -L -l2 /2 width=1/
-| #L #K #V #W #U1 #i #l1 #HLK #_ #HWU1 #IHVW #U2 #l2 #H
- elim (ssta_inv_lref1 … H) -H * #K0 #V0 #W0 [2: #l0] #HLK0 #HVW0 #HW0U2
+theorem ssta_mono: ∀h,g,G,L. singlevalued … (ssta h g G L).
+#h #g #G #L #T #U1 #H elim H -G -L -T -U1
+[ #G #L #k #X #H >(ssta_inv_sort1 … H) -X //
+| #G #L #K #V #U1 #W #i #HLK #_ #HWU1 #IHVW #U2 #H
+ elim (ssta_inv_lref1 … H) -H * #K0 #V0 #W0 #HLK0 #HVW0 #HW0U2