∃∃L2. G ⊢ L1 ⫃[RP] L2 & ⬇*[Ⓕ, des] L2 ≡ K2.
#RR #RS #RP #Hgcp #G #L1 #K1 #des #H elim H -L1 -K1 -des
[ /2 width=3 by drops_nil, ex2_intro/
-| #L1 #L #K1 #des #d #e #_ #HLK1 #IHL #K2 #HK12
+| #L1 #L #K1 #des #l #m #_ #HLK1 #IHL #K2 #HK12
elim (drop_lsubc_trans … Hgcp … HLK1 … HK12) -Hgcp -K1 #K #HLK #HK2
elim (IHL … HLK) -IHL -HLK /3 width=5 by drops_cons, ex2_intro/
]