| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 2fveq3 | Could not format  ( x = xO -> ( bday ` ( -us ` x ) ) = ( bday ` ( -us ` xO ) ) ) : No typesetting found for |- ( x = xO -> ( bday ` ( -us ` x ) ) = ( bday ` ( -us ` xO ) ) ) with typecode |- | 
						
							| 2 |  | fveq2 | Could not format  ( x = xO -> ( bday ` x ) = ( bday ` xO ) ) : No typesetting found for |- ( x = xO -> ( bday ` x ) = ( bday ` xO ) ) with typecode |- | 
						
							| 3 | 1 2 | sseq12d | Could not format  ( x = xO -> ( ( bday ` ( -us ` x ) ) C_ ( bday ` x ) <-> ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) ) ) : No typesetting found for |- ( x = xO -> ( ( bday ` ( -us ` x ) ) C_ ( bday ` x ) <-> ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) ) ) with typecode |- | 
						
							| 4 |  | 2fveq3 |  | 
						
							| 5 |  | fveq2 |  | 
						
							| 6 | 4 5 | sseq12d |  | 
						
							| 7 |  | negsval |  | 
						
							| 8 | 7 | fveq2d |  | 
						
							| 9 | 8 | adantr | Could not format  ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) ) -> ( bday ` ( -us ` x ) ) = ( bday ` ( ( -us " ( _Right ` x ) ) |s ( -us " ( _Left ` x ) ) ) ) ) : No typesetting found for |- ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) ) -> ( bday ` ( -us ` x ) ) = ( bday ` ( ( -us " ( _Right ` x ) ) |s ( -us " ( _Left ` x ) ) ) ) ) with typecode |- | 
						
							| 10 |  | negscut2 |  | 
						
							| 11 |  | lrold |  | 
						
							| 12 |  | uncom |  | 
						
							| 13 | 11 12 | eqtr3i |  | 
						
							| 14 | 13 | imaeq2i |  | 
						
							| 15 |  | imaundi |  | 
						
							| 16 | 14 15 | eqtri |  | 
						
							| 17 | 16 | imaeq2i |  | 
						
							| 18 | 11 | raleqi | Could not format  ( A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) <-> A. xO e. ( _Old ` ( bday ` x ) ) ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) ) : No typesetting found for |- ( A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) <-> A. xO e. ( _Old ` ( bday ` x ) ) ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) ) with typecode |- | 
						
							| 19 |  | oldbdayim | Could not format  ( xO e. ( _Old ` ( bday ` x ) ) -> ( bday ` xO ) e. ( bday ` x ) ) : No typesetting found for |- ( xO e. ( _Old ` ( bday ` x ) ) -> ( bday ` xO ) e. ( bday ` x ) ) with typecode |- | 
						
							| 20 | 19 | adantl | Could not format  ( ( x e. No /\ xO e. ( _Old ` ( bday ` x ) ) ) -> ( bday ` xO ) e. ( bday ` x ) ) : No typesetting found for |- ( ( x e. No /\ xO e. ( _Old ` ( bday ` x ) ) ) -> ( bday ` xO ) e. ( bday ` x ) ) with typecode |- | 
						
							| 21 |  | bdayelon | Could not format  ( bday ` ( -us ` xO ) ) e. On : No typesetting found for |- ( bday ` ( -us ` xO ) ) e. On with typecode |- | 
						
							| 22 |  | bdayelon |  | 
						
							| 23 |  | ontr2 | Could not format  ( ( ( bday ` ( -us ` xO ) ) e. On /\ ( bday ` x ) e. On ) -> ( ( ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) /\ ( bday ` xO ) e. ( bday ` x ) ) -> ( bday ` ( -us ` xO ) ) e. ( bday ` x ) ) ) : No typesetting found for |- ( ( ( bday ` ( -us ` xO ) ) e. On /\ ( bday ` x ) e. On ) -> ( ( ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) /\ ( bday ` xO ) e. ( bday ` x ) ) -> ( bday ` ( -us ` xO ) ) e. ( bday ` x ) ) ) with typecode |- | 
						
							| 24 | 21 22 23 | mp2an | Could not format  ( ( ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) /\ ( bday ` xO ) e. ( bday ` x ) ) -> ( bday ` ( -us ` xO ) ) e. ( bday ` x ) ) : No typesetting found for |- ( ( ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) /\ ( bday ` xO ) e. ( bday ` x ) ) -> ( bday ` ( -us ` xO ) ) e. ( bday ` x ) ) with typecode |- | 
						
							| 25 | 24 | a1i | Could not format  ( ( x e. No /\ xO e. ( _Old ` ( bday ` x ) ) ) -> ( ( ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) /\ ( bday ` xO ) e. ( bday ` x ) ) -> ( bday ` ( -us ` xO ) ) e. ( bday ` x ) ) ) : No typesetting found for |- ( ( x e. No /\ xO e. ( _Old ` ( bday ` x ) ) ) -> ( ( ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) /\ ( bday ` xO ) e. ( bday ` x ) ) -> ( bday ` ( -us ` xO ) ) e. ( bday ` x ) ) ) with typecode |- | 
						
							| 26 | 20 25 | mpan2d | Could not format  ( ( x e. No /\ xO e. ( _Old ` ( bday ` x ) ) ) -> ( ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) -> ( bday ` ( -us ` xO ) ) e. ( bday ` x ) ) ) : No typesetting found for |- ( ( x e. No /\ xO e. ( _Old ` ( bday ` x ) ) ) -> ( ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) -> ( bday ` ( -us ` xO ) ) e. ( bday ` x ) ) ) with typecode |- | 
						
							| 27 | 26 | ralimdva | Could not format  ( x e. No -> ( A. xO e. ( _Old ` ( bday ` x ) ) ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) -> A. xO e. ( _Old ` ( bday ` x ) ) ( bday ` ( -us ` xO ) ) e. ( bday ` x ) ) ) : No typesetting found for |- ( x e. No -> ( A. xO e. ( _Old ` ( bday ` x ) ) ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) -> A. xO e. ( _Old ` ( bday ` x ) ) ( bday ` ( -us ` xO ) ) e. ( bday ` x ) ) ) with typecode |- | 
						
							| 28 | 27 | imp | Could not format  ( ( x e. No /\ A. xO e. ( _Old ` ( bday ` x ) ) ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) ) -> A. xO e. ( _Old ` ( bday ` x ) ) ( bday ` ( -us ` xO ) ) e. ( bday ` x ) ) : No typesetting found for |- ( ( x e. No /\ A. xO e. ( _Old ` ( bday ` x ) ) ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) ) -> A. xO e. ( _Old ` ( bday ` x ) ) ( bday ` ( -us ` xO ) ) e. ( bday ` x ) ) with typecode |- | 
						
							| 29 |  | bdayfun |  | 
						
							| 30 |  | imassrn |  | 
						
							| 31 |  | bdaydm |  | 
						
							| 32 |  | negsfo |  | 
						
							| 33 |  | forn |  | 
						
							| 34 | 32 33 | ax-mp |  | 
						
							| 35 | 31 34 | eqtr4i |  | 
						
							| 36 | 30 35 | sseqtrri |  | 
						
							| 37 |  | funimass4 |  | 
						
							| 38 | 29 36 37 | mp2an |  | 
						
							| 39 |  | negsfn |  | 
						
							| 40 |  | oldssno |  | 
						
							| 41 |  | fveq2 | Could not format  ( y = ( -us ` xO ) -> ( bday ` y ) = ( bday ` ( -us ` xO ) ) ) : No typesetting found for |- ( y = ( -us ` xO ) -> ( bday ` y ) = ( bday ` ( -us ` xO ) ) ) with typecode |- | 
						
							| 42 | 41 | eleq1d | Could not format  ( y = ( -us ` xO ) -> ( ( bday ` y ) e. ( bday ` x ) <-> ( bday ` ( -us ` xO ) ) e. ( bday ` x ) ) ) : No typesetting found for |- ( y = ( -us ` xO ) -> ( ( bday ` y ) e. ( bday ` x ) <-> ( bday ` ( -us ` xO ) ) e. ( bday ` x ) ) ) with typecode |- | 
						
							| 43 | 42 | ralima | Could not format  ( ( -us Fn No /\ ( _Old ` ( bday ` x ) ) C_ No ) -> ( A. y e. ( -us " ( _Old ` ( bday ` x ) ) ) ( bday ` y ) e. ( bday ` x ) <-> A. xO e. ( _Old ` ( bday ` x ) ) ( bday ` ( -us ` xO ) ) e. ( bday ` x ) ) ) : No typesetting found for |- ( ( -us Fn No /\ ( _Old ` ( bday ` x ) ) C_ No ) -> ( A. y e. ( -us " ( _Old ` ( bday ` x ) ) ) ( bday ` y ) e. ( bday ` x ) <-> A. xO e. ( _Old ` ( bday ` x ) ) ( bday ` ( -us ` xO ) ) e. ( bday ` x ) ) ) with typecode |- | 
						
							| 44 | 39 40 43 | mp2an | Could not format  ( A. y e. ( -us " ( _Old ` ( bday ` x ) ) ) ( bday ` y ) e. ( bday ` x ) <-> A. xO e. ( _Old ` ( bday ` x ) ) ( bday ` ( -us ` xO ) ) e. ( bday ` x ) ) : No typesetting found for |- ( A. y e. ( -us " ( _Old ` ( bday ` x ) ) ) ( bday ` y ) e. ( bday ` x ) <-> A. xO e. ( _Old ` ( bday ` x ) ) ( bday ` ( -us ` xO ) ) e. ( bday ` x ) ) with typecode |- | 
						
							| 45 | 38 44 | bitri | Could not format  ( ( bday " ( -us " ( _Old ` ( bday ` x ) ) ) ) C_ ( bday ` x ) <-> A. xO e. ( _Old ` ( bday ` x ) ) ( bday ` ( -us ` xO ) ) e. ( bday ` x ) ) : No typesetting found for |- ( ( bday " ( -us " ( _Old ` ( bday ` x ) ) ) ) C_ ( bday ` x ) <-> A. xO e. ( _Old ` ( bday ` x ) ) ( bday ` ( -us ` xO ) ) e. ( bday ` x ) ) with typecode |- | 
						
							| 46 | 28 45 | sylibr | Could not format  ( ( x e. No /\ A. xO e. ( _Old ` ( bday ` x ) ) ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) ) -> ( bday " ( -us " ( _Old ` ( bday ` x ) ) ) ) C_ ( bday ` x ) ) : No typesetting found for |- ( ( x e. No /\ A. xO e. ( _Old ` ( bday ` x ) ) ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) ) -> ( bday " ( -us " ( _Old ` ( bday ` x ) ) ) ) C_ ( bday ` x ) ) with typecode |- | 
						
							| 47 | 18 46 | sylan2b | Could not format  ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) ) -> ( bday " ( -us " ( _Old ` ( bday ` x ) ) ) ) C_ ( bday ` x ) ) : No typesetting found for |- ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) ) -> ( bday " ( -us " ( _Old ` ( bday ` x ) ) ) ) C_ ( bday ` x ) ) with typecode |- | 
						
							| 48 | 17 47 | eqsstrrid | Could not format  ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) ) -> ( bday " ( ( -us " ( _Right ` x ) ) u. ( -us " ( _Left ` x ) ) ) ) C_ ( bday ` x ) ) : No typesetting found for |- ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) ) -> ( bday " ( ( -us " ( _Right ` x ) ) u. ( -us " ( _Left ` x ) ) ) ) C_ ( bday ` x ) ) with typecode |- | 
						
							| 49 |  | scutbdaybnd |  | 
						
							| 50 | 22 49 | mp3an2 |  | 
						
							| 51 | 10 48 50 | syl2an2r | Could not format  ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) ) -> ( bday ` ( ( -us " ( _Right ` x ) ) |s ( -us " ( _Left ` x ) ) ) ) C_ ( bday ` x ) ) : No typesetting found for |- ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) ) -> ( bday ` ( ( -us " ( _Right ` x ) ) |s ( -us " ( _Left ` x ) ) ) ) C_ ( bday ` x ) ) with typecode |- | 
						
							| 52 | 9 51 | eqsstrd | Could not format  ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) ) -> ( bday ` ( -us ` x ) ) C_ ( bday ` x ) ) : No typesetting found for |- ( ( x e. No /\ A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) ) -> ( bday ` ( -us ` x ) ) C_ ( bday ` x ) ) with typecode |- | 
						
							| 53 | 52 | ex | Could not format  ( x e. No -> ( A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) -> ( bday ` ( -us ` x ) ) C_ ( bday ` x ) ) ) : No typesetting found for |- ( x e. No -> ( A. xO e. ( ( _Left ` x ) u. ( _Right ` x ) ) ( bday ` ( -us ` xO ) ) C_ ( bday ` xO ) -> ( bday ` ( -us ` x ) ) C_ ( bday ` x ) ) ) with typecode |- | 
						
							| 54 | 3 6 53 | noinds |  |