| Step | Hyp | Ref | Expression | 
						
							| 1 |  | phplem2OLD.1 |  |-  A e. _V | 
						
							| 2 |  | phplem2OLD.2 |  |-  B e. _V | 
						
							| 3 |  | bren |  |-  ( suc A ~~ suc B <-> E. f f : suc A -1-1-onto-> suc B ) | 
						
							| 4 |  | f1of1 |  |-  ( f : suc A -1-1-onto-> suc B -> f : suc A -1-1-> suc B ) | 
						
							| 5 | 4 | adantl |  |-  ( ( A e. _om /\ f : suc A -1-1-onto-> suc B ) -> f : suc A -1-1-> suc B ) | 
						
							| 6 | 2 | sucex |  |-  suc B e. _V | 
						
							| 7 |  | sssucid |  |-  A C_ suc A | 
						
							| 8 |  | f1imaen2g |  |-  ( ( ( f : suc A -1-1-> suc B /\ suc B e. _V ) /\ ( A C_ suc A /\ A e. _V ) ) -> ( f " A ) ~~ A ) | 
						
							| 9 | 7 1 8 | mpanr12 |  |-  ( ( f : suc A -1-1-> suc B /\ suc B e. _V ) -> ( f " A ) ~~ A ) | 
						
							| 10 | 5 6 9 | sylancl |  |-  ( ( A e. _om /\ f : suc A -1-1-onto-> suc B ) -> ( f " A ) ~~ A ) | 
						
							| 11 | 10 | ensymd |  |-  ( ( A e. _om /\ f : suc A -1-1-onto-> suc B ) -> A ~~ ( f " A ) ) | 
						
							| 12 |  | nnord |  |-  ( A e. _om -> Ord A ) | 
						
							| 13 |  | orddif |  |-  ( Ord A -> A = ( suc A \ { A } ) ) | 
						
							| 14 | 12 13 | syl |  |-  ( A e. _om -> A = ( suc A \ { A } ) ) | 
						
							| 15 | 14 | imaeq2d |  |-  ( A e. _om -> ( f " A ) = ( f " ( suc A \ { A } ) ) ) | 
						
							| 16 |  | f1ofn |  |-  ( f : suc A -1-1-onto-> suc B -> f Fn suc A ) | 
						
							| 17 | 1 | sucid |  |-  A e. suc A | 
						
							| 18 |  | fnsnfv |  |-  ( ( f Fn suc A /\ A e. suc A ) -> { ( f ` A ) } = ( f " { A } ) ) | 
						
							| 19 | 16 17 18 | sylancl |  |-  ( f : suc A -1-1-onto-> suc B -> { ( f ` A ) } = ( f " { A } ) ) | 
						
							| 20 | 19 | difeq2d |  |-  ( f : suc A -1-1-onto-> suc B -> ( ( f " suc A ) \ { ( f ` A ) } ) = ( ( f " suc A ) \ ( f " { A } ) ) ) | 
						
							| 21 |  | imadmrn |  |-  ( f " dom f ) = ran f | 
						
							| 22 | 21 | eqcomi |  |-  ran f = ( f " dom f ) | 
						
							| 23 |  | f1ofo |  |-  ( f : suc A -1-1-onto-> suc B -> f : suc A -onto-> suc B ) | 
						
							| 24 |  | forn |  |-  ( f : suc A -onto-> suc B -> ran f = suc B ) | 
						
							| 25 | 23 24 | syl |  |-  ( f : suc A -1-1-onto-> suc B -> ran f = suc B ) | 
						
							| 26 |  | f1odm |  |-  ( f : suc A -1-1-onto-> suc B -> dom f = suc A ) | 
						
							| 27 | 26 | imaeq2d |  |-  ( f : suc A -1-1-onto-> suc B -> ( f " dom f ) = ( f " suc A ) ) | 
						
							| 28 | 22 25 27 | 3eqtr3a |  |-  ( f : suc A -1-1-onto-> suc B -> suc B = ( f " suc A ) ) | 
						
							| 29 | 28 | difeq1d |  |-  ( f : suc A -1-1-onto-> suc B -> ( suc B \ { ( f ` A ) } ) = ( ( f " suc A ) \ { ( f ` A ) } ) ) | 
						
							| 30 |  | dff1o3 |  |-  ( f : suc A -1-1-onto-> suc B <-> ( f : suc A -onto-> suc B /\ Fun `' f ) ) | 
						
							| 31 |  | imadif |  |-  ( Fun `' f -> ( f " ( suc A \ { A } ) ) = ( ( f " suc A ) \ ( f " { A } ) ) ) | 
						
							| 32 | 30 31 | simplbiim |  |-  ( f : suc A -1-1-onto-> suc B -> ( f " ( suc A \ { A } ) ) = ( ( f " suc A ) \ ( f " { A } ) ) ) | 
						
							| 33 | 20 29 32 | 3eqtr4rd |  |-  ( f : suc A -1-1-onto-> suc B -> ( f " ( suc A \ { A } ) ) = ( suc B \ { ( f ` A ) } ) ) | 
						
							| 34 | 15 33 | sylan9eq |  |-  ( ( A e. _om /\ f : suc A -1-1-onto-> suc B ) -> ( f " A ) = ( suc B \ { ( f ` A ) } ) ) | 
						
							| 35 | 11 34 | breqtrd |  |-  ( ( A e. _om /\ f : suc A -1-1-onto-> suc B ) -> A ~~ ( suc B \ { ( f ` A ) } ) ) | 
						
							| 36 |  | fnfvelrn |  |-  ( ( f Fn suc A /\ A e. suc A ) -> ( f ` A ) e. ran f ) | 
						
							| 37 | 16 17 36 | sylancl |  |-  ( f : suc A -1-1-onto-> suc B -> ( f ` A ) e. ran f ) | 
						
							| 38 | 24 | eleq2d |  |-  ( f : suc A -onto-> suc B -> ( ( f ` A ) e. ran f <-> ( f ` A ) e. suc B ) ) | 
						
							| 39 | 23 38 | syl |  |-  ( f : suc A -1-1-onto-> suc B -> ( ( f ` A ) e. ran f <-> ( f ` A ) e. suc B ) ) | 
						
							| 40 | 37 39 | mpbid |  |-  ( f : suc A -1-1-onto-> suc B -> ( f ` A ) e. suc B ) | 
						
							| 41 |  | fvex |  |-  ( f ` A ) e. _V | 
						
							| 42 | 2 41 | phplem3OLD |  |-  ( ( B e. _om /\ ( f ` A ) e. suc B ) -> B ~~ ( suc B \ { ( f ` A ) } ) ) | 
						
							| 43 | 40 42 | sylan2 |  |-  ( ( B e. _om /\ f : suc A -1-1-onto-> suc B ) -> B ~~ ( suc B \ { ( f ` A ) } ) ) | 
						
							| 44 | 43 | ensymd |  |-  ( ( B e. _om /\ f : suc A -1-1-onto-> suc B ) -> ( suc B \ { ( f ` A ) } ) ~~ B ) | 
						
							| 45 |  | entr |  |-  ( ( A ~~ ( suc B \ { ( f ` A ) } ) /\ ( suc B \ { ( f ` A ) } ) ~~ B ) -> A ~~ B ) | 
						
							| 46 | 35 44 45 | syl2an |  |-  ( ( ( A e. _om /\ f : suc A -1-1-onto-> suc B ) /\ ( B e. _om /\ f : suc A -1-1-onto-> suc B ) ) -> A ~~ B ) | 
						
							| 47 | 46 | anandirs |  |-  ( ( ( A e. _om /\ B e. _om ) /\ f : suc A -1-1-onto-> suc B ) -> A ~~ B ) | 
						
							| 48 | 47 | ex |  |-  ( ( A e. _om /\ B e. _om ) -> ( f : suc A -1-1-onto-> suc B -> A ~~ B ) ) | 
						
							| 49 | 48 | exlimdv |  |-  ( ( A e. _om /\ B e. _om ) -> ( E. f f : suc A -1-1-onto-> suc B -> A ~~ B ) ) | 
						
							| 50 | 3 49 | biimtrid |  |-  ( ( A e. _om /\ B e. _om ) -> ( suc A ~~ suc B -> A ~~ B ) ) |