| Step | Hyp | Ref | Expression | 
						
							| 1 |  | wunress.1 |  |-  ( ph -> U e. WUni ) | 
						
							| 2 |  | wunress.2 |  |-  ( ph -> _om e. U ) | 
						
							| 3 |  | wunress.3 |  |-  ( ph -> W e. U ) | 
						
							| 4 |  | eqid |  |-  ( W |`s A ) = ( W |`s A ) | 
						
							| 5 |  | eqid |  |-  ( Base ` W ) = ( Base ` W ) | 
						
							| 6 | 4 5 | ressval |  |-  ( ( W e. U /\ A e. _V ) -> ( W |`s A ) = if ( ( Base ` W ) C_ A , W , ( W sSet <. ( Base ` ndx ) , ( A i^i ( Base ` W ) ) >. ) ) ) | 
						
							| 7 | 3 6 | sylan |  |-  ( ( ph /\ A e. _V ) -> ( W |`s A ) = if ( ( Base ` W ) C_ A , W , ( W sSet <. ( Base ` ndx ) , ( A i^i ( Base ` W ) ) >. ) ) ) | 
						
							| 8 |  | df-base |  |-  Base = Slot 1 | 
						
							| 9 | 1 2 | wunndx |  |-  ( ph -> ndx e. U ) | 
						
							| 10 | 8 1 9 | wunstr |  |-  ( ph -> ( Base ` ndx ) e. U ) | 
						
							| 11 |  | incom |  |-  ( A i^i ( Base ` W ) ) = ( ( Base ` W ) i^i A ) | 
						
							| 12 |  | baseid |  |-  Base = Slot ( Base ` ndx ) | 
						
							| 13 | 12 1 3 | wunstr |  |-  ( ph -> ( Base ` W ) e. U ) | 
						
							| 14 | 1 13 | wunin |  |-  ( ph -> ( ( Base ` W ) i^i A ) e. U ) | 
						
							| 15 | 11 14 | eqeltrid |  |-  ( ph -> ( A i^i ( Base ` W ) ) e. U ) | 
						
							| 16 | 1 10 15 | wunop |  |-  ( ph -> <. ( Base ` ndx ) , ( A i^i ( Base ` W ) ) >. e. U ) | 
						
							| 17 | 1 3 16 | wunsets |  |-  ( ph -> ( W sSet <. ( Base ` ndx ) , ( A i^i ( Base ` W ) ) >. ) e. U ) | 
						
							| 18 | 3 17 | ifcld |  |-  ( ph -> if ( ( Base ` W ) C_ A , W , ( W sSet <. ( Base ` ndx ) , ( A i^i ( Base ` W ) ) >. ) ) e. U ) | 
						
							| 19 | 18 | adantr |  |-  ( ( ph /\ A e. _V ) -> if ( ( Base ` W ) C_ A , W , ( W sSet <. ( Base ` ndx ) , ( A i^i ( Base ` W ) ) >. ) ) e. U ) | 
						
							| 20 | 7 19 | eqeltrd |  |-  ( ( ph /\ A e. _V ) -> ( W |`s A ) e. U ) | 
						
							| 21 | 20 | ex |  |-  ( ph -> ( A e. _V -> ( W |`s A ) e. U ) ) | 
						
							| 22 | 1 | wun0 |  |-  ( ph -> (/) e. U ) | 
						
							| 23 |  | reldmress |  |-  Rel dom |`s | 
						
							| 24 | 23 | ovprc2 |  |-  ( -. A e. _V -> ( W |`s A ) = (/) ) | 
						
							| 25 | 24 | eleq1d |  |-  ( -. A e. _V -> ( ( W |`s A ) e. U <-> (/) e. U ) ) | 
						
							| 26 | 22 25 | syl5ibrcom |  |-  ( ph -> ( -. A e. _V -> ( W |`s A ) e. U ) ) | 
						
							| 27 | 21 26 | pm2.61d |  |-  ( ph -> ( W |`s A ) e. U ) |