| Step | Hyp | Ref | Expression | 
						
							| 1 |  | addsproplem.1 |  |-  ( ph -> A. x e. No A. y e. No A. z e. No ( ( ( ( bday ` x ) +no ( bday ` y ) ) u. ( ( bday ` x ) +no ( bday ` z ) ) ) e. ( ( ( bday ` X ) +no ( bday ` Y ) ) u. ( ( bday ` X ) +no ( bday ` Z ) ) ) -> ( ( x +s y ) e. No /\ ( y  ( y +s x )  | 
						
							| 2 |  | addspropord.2 |  |-  ( ph -> X e. No ) | 
						
							| 3 |  | addspropord.3 |  |-  ( ph -> Y e. No ) | 
						
							| 4 |  | addspropord.4 |  |-  ( ph -> Z e. No ) | 
						
							| 5 |  | addspropord.5 |  |-  ( ph -> Y  | 
						
							| 6 |  | bdayelon |  |-  ( bday ` Y ) e. On | 
						
							| 7 |  | fvex |  |-  ( bday ` Y ) e. _V | 
						
							| 8 | 7 | elon |  |-  ( ( bday ` Y ) e. On <-> Ord ( bday ` Y ) ) | 
						
							| 9 | 6 8 | mpbi |  |-  Ord ( bday ` Y ) | 
						
							| 10 |  | bdayelon |  |-  ( bday ` Z ) e. On | 
						
							| 11 |  | fvex |  |-  ( bday ` Z ) e. _V | 
						
							| 12 | 11 | elon |  |-  ( ( bday ` Z ) e. On <-> Ord ( bday ` Z ) ) | 
						
							| 13 | 10 12 | mpbi |  |-  Ord ( bday ` Z ) | 
						
							| 14 |  | ordtri3or |  |-  ( ( Ord ( bday ` Y ) /\ Ord ( bday ` Z ) ) -> ( ( bday ` Y ) e. ( bday ` Z ) \/ ( bday ` Y ) = ( bday ` Z ) \/ ( bday ` Z ) e. ( bday ` Y ) ) ) | 
						
							| 15 | 9 13 14 | mp2an |  |-  ( ( bday ` Y ) e. ( bday ` Z ) \/ ( bday ` Y ) = ( bday ` Z ) \/ ( bday ` Z ) e. ( bday ` Y ) ) | 
						
							| 16 |  | simpl |  |-  ( ( ph /\ ( bday ` Y ) e. ( bday ` Z ) ) -> ph ) | 
						
							| 17 | 16 1 | syl |  |-  ( ( ph /\ ( bday ` Y ) e. ( bday ` Z ) ) -> A. x e. No A. y e. No A. z e. No ( ( ( ( bday ` x ) +no ( bday ` y ) ) u. ( ( bday ` x ) +no ( bday ` z ) ) ) e. ( ( ( bday ` X ) +no ( bday ` Y ) ) u. ( ( bday ` X ) +no ( bday ` Z ) ) ) -> ( ( x +s y ) e. No /\ ( y  ( y +s x )  | 
						
							| 18 | 16 2 | syl |  |-  ( ( ph /\ ( bday ` Y ) e. ( bday ` Z ) ) -> X e. No ) | 
						
							| 19 | 16 3 | syl |  |-  ( ( ph /\ ( bday ` Y ) e. ( bday ` Z ) ) -> Y e. No ) | 
						
							| 20 | 16 4 | syl |  |-  ( ( ph /\ ( bday ` Y ) e. ( bday ` Z ) ) -> Z e. No ) | 
						
							| 21 | 16 5 | syl |  |-  ( ( ph /\ ( bday ` Y ) e. ( bday ` Z ) ) -> Y  | 
						
							| 22 |  | simpr |  |-  ( ( ph /\ ( bday ` Y ) e. ( bday ` Z ) ) -> ( bday ` Y ) e. ( bday ` Z ) ) | 
						
							| 23 | 17 18 19 20 21 22 | addsproplem4 |  |-  ( ( ph /\ ( bday ` Y ) e. ( bday ` Z ) ) -> ( Y +s X )  | 
						
							| 24 | 23 | ex |  |-  ( ph -> ( ( bday ` Y ) e. ( bday ` Z ) -> ( Y +s X )  | 
						
							| 25 |  | simpl |  |-  ( ( ph /\ ( bday ` Y ) = ( bday ` Z ) ) -> ph ) | 
						
							| 26 | 25 1 | syl |  |-  ( ( ph /\ ( bday ` Y ) = ( bday ` Z ) ) -> A. x e. No A. y e. No A. z e. No ( ( ( ( bday ` x ) +no ( bday ` y ) ) u. ( ( bday ` x ) +no ( bday ` z ) ) ) e. ( ( ( bday ` X ) +no ( bday ` Y ) ) u. ( ( bday ` X ) +no ( bday ` Z ) ) ) -> ( ( x +s y ) e. No /\ ( y  ( y +s x )  | 
						
							| 27 | 25 2 | syl |  |-  ( ( ph /\ ( bday ` Y ) = ( bday ` Z ) ) -> X e. No ) | 
						
							| 28 | 25 3 | syl |  |-  ( ( ph /\ ( bday ` Y ) = ( bday ` Z ) ) -> Y e. No ) | 
						
							| 29 | 25 4 | syl |  |-  ( ( ph /\ ( bday ` Y ) = ( bday ` Z ) ) -> Z e. No ) | 
						
							| 30 | 25 5 | syl |  |-  ( ( ph /\ ( bday ` Y ) = ( bday ` Z ) ) -> Y  | 
						
							| 31 |  | simpr |  |-  ( ( ph /\ ( bday ` Y ) = ( bday ` Z ) ) -> ( bday ` Y ) = ( bday ` Z ) ) | 
						
							| 32 | 26 27 28 29 30 31 | addsproplem6 |  |-  ( ( ph /\ ( bday ` Y ) = ( bday ` Z ) ) -> ( Y +s X )  | 
						
							| 33 | 32 | ex |  |-  ( ph -> ( ( bday ` Y ) = ( bday ` Z ) -> ( Y +s X )  | 
						
							| 34 | 1 | adantr |  |-  ( ( ph /\ ( bday ` Z ) e. ( bday ` Y ) ) -> A. x e. No A. y e. No A. z e. No ( ( ( ( bday ` x ) +no ( bday ` y ) ) u. ( ( bday ` x ) +no ( bday ` z ) ) ) e. ( ( ( bday ` X ) +no ( bday ` Y ) ) u. ( ( bday ` X ) +no ( bday ` Z ) ) ) -> ( ( x +s y ) e. No /\ ( y  ( y +s x )  | 
						
							| 35 | 2 | adantr |  |-  ( ( ph /\ ( bday ` Z ) e. ( bday ` Y ) ) -> X e. No ) | 
						
							| 36 | 3 | adantr |  |-  ( ( ph /\ ( bday ` Z ) e. ( bday ` Y ) ) -> Y e. No ) | 
						
							| 37 | 4 | adantr |  |-  ( ( ph /\ ( bday ` Z ) e. ( bday ` Y ) ) -> Z e. No ) | 
						
							| 38 | 5 | adantr |  |-  ( ( ph /\ ( bday ` Z ) e. ( bday ` Y ) ) -> Y  | 
						
							| 39 |  | simpr |  |-  ( ( ph /\ ( bday ` Z ) e. ( bday ` Y ) ) -> ( bday ` Z ) e. ( bday ` Y ) ) | 
						
							| 40 | 34 35 36 37 38 39 | addsproplem5 |  |-  ( ( ph /\ ( bday ` Z ) e. ( bday ` Y ) ) -> ( Y +s X )  | 
						
							| 41 | 40 | ex |  |-  ( ph -> ( ( bday ` Z ) e. ( bday ` Y ) -> ( Y +s X )  | 
						
							| 42 | 24 33 41 | 3jaod |  |-  ( ph -> ( ( ( bday ` Y ) e. ( bday ` Z ) \/ ( bday ` Y ) = ( bday ` Z ) \/ ( bday ` Z ) e. ( bday ` Y ) ) -> ( Y +s X )  | 
						
							| 43 | 15 42 | mpi |  |-  ( ph -> ( Y +s X )  |