| Step | Hyp | Ref | Expression | 
						
							| 1 |  | suppss2f.p |  |-  F/ k ph | 
						
							| 2 |  | suppss2f.a |  |-  F/_ k A | 
						
							| 3 |  | suppss2f.w |  |-  F/_ k W | 
						
							| 4 |  | suppss2f.n |  |-  ( ( ph /\ k e. ( A \ W ) ) -> B = Z ) | 
						
							| 5 |  | suppss2f.v |  |-  ( ph -> A e. V ) | 
						
							| 6 |  | nfcv |  |-  F/_ l A | 
						
							| 7 |  | nfcv |  |-  F/_ l B | 
						
							| 8 |  | nfcsb1v |  |-  F/_ k [_ l / k ]_ B | 
						
							| 9 |  | csbeq1a |  |-  ( k = l -> B = [_ l / k ]_ B ) | 
						
							| 10 | 2 6 7 8 9 | cbvmptf |  |-  ( k e. A |-> B ) = ( l e. A |-> [_ l / k ]_ B ) | 
						
							| 11 | 10 | oveq1i |  |-  ( ( k e. A |-> B ) supp Z ) = ( ( l e. A |-> [_ l / k ]_ B ) supp Z ) | 
						
							| 12 | 4 | sbt |  |-  [ l / k ] ( ( ph /\ k e. ( A \ W ) ) -> B = Z ) | 
						
							| 13 |  | sbim |  |-  ( [ l / k ] ( ( ph /\ k e. ( A \ W ) ) -> B = Z ) <-> ( [ l / k ] ( ph /\ k e. ( A \ W ) ) -> [ l / k ] B = Z ) ) | 
						
							| 14 |  | sban |  |-  ( [ l / k ] ( ph /\ k e. ( A \ W ) ) <-> ( [ l / k ] ph /\ [ l / k ] k e. ( A \ W ) ) ) | 
						
							| 15 | 1 | sbf |  |-  ( [ l / k ] ph <-> ph ) | 
						
							| 16 | 2 3 | nfdif |  |-  F/_ k ( A \ W ) | 
						
							| 17 | 16 | clelsb1fw |  |-  ( [ l / k ] k e. ( A \ W ) <-> l e. ( A \ W ) ) | 
						
							| 18 | 15 17 | anbi12i |  |-  ( ( [ l / k ] ph /\ [ l / k ] k e. ( A \ W ) ) <-> ( ph /\ l e. ( A \ W ) ) ) | 
						
							| 19 | 14 18 | bitri |  |-  ( [ l / k ] ( ph /\ k e. ( A \ W ) ) <-> ( ph /\ l e. ( A \ W ) ) ) | 
						
							| 20 |  | sbsbc |  |-  ( [ l / k ] B = Z <-> [. l / k ]. B = Z ) | 
						
							| 21 |  | sbceq1g |  |-  ( l e. _V -> ( [. l / k ]. B = Z <-> [_ l / k ]_ B = Z ) ) | 
						
							| 22 | 21 | elv |  |-  ( [. l / k ]. B = Z <-> [_ l / k ]_ B = Z ) | 
						
							| 23 | 20 22 | bitri |  |-  ( [ l / k ] B = Z <-> [_ l / k ]_ B = Z ) | 
						
							| 24 | 19 23 | imbi12i |  |-  ( ( [ l / k ] ( ph /\ k e. ( A \ W ) ) -> [ l / k ] B = Z ) <-> ( ( ph /\ l e. ( A \ W ) ) -> [_ l / k ]_ B = Z ) ) | 
						
							| 25 | 13 24 | bitri |  |-  ( [ l / k ] ( ( ph /\ k e. ( A \ W ) ) -> B = Z ) <-> ( ( ph /\ l e. ( A \ W ) ) -> [_ l / k ]_ B = Z ) ) | 
						
							| 26 | 12 25 | mpbi |  |-  ( ( ph /\ l e. ( A \ W ) ) -> [_ l / k ]_ B = Z ) | 
						
							| 27 | 26 5 | suppss2 |  |-  ( ph -> ( ( l e. A |-> [_ l / k ]_ B ) supp Z ) C_ W ) | 
						
							| 28 | 11 27 | eqsstrid |  |-  ( ph -> ( ( k e. A |-> B ) supp Z ) C_ W ) |