| Step | Hyp | Ref | Expression | 
						
							| 1 |  | addsproplem.1 |  | 
						
							| 2 |  | addspropord.2 |  | 
						
							| 3 |  | addspropord.3 |  | 
						
							| 4 |  | addspropord.4 |  | 
						
							| 5 |  | addspropord.5 |  | 
						
							| 6 |  | addsproplem4.6 |  | 
						
							| 7 |  | uncom |  | 
						
							| 8 | 7 | eleq2i |  | 
						
							| 9 | 8 | imbi1i |  | 
						
							| 10 | 9 | ralbii |  | 
						
							| 11 | 10 | 2ralbii |  | 
						
							| 12 | 1 11 | sylib |  | 
						
							| 13 | 12 2 4 | addsproplem3 |  | 
						
							| 14 | 13 | simp2d |  | 
						
							| 15 |  | bdayelon |  | 
						
							| 16 |  | oldbday |  | 
						
							| 17 | 15 3 16 | sylancr |  | 
						
							| 18 | 6 17 | mpbird |  | 
						
							| 19 |  | breq1 |  | 
						
							| 20 |  | leftval |  | 
						
							| 21 | 19 20 | elrab2 |  | 
						
							| 22 | 18 5 21 | sylanbrc |  | 
						
							| 23 |  | eqid |  | 
						
							| 24 |  | oveq2 |  | 
						
							| 25 | 24 | rspceeqv |  | 
						
							| 26 | 22 23 25 | sylancl |  | 
						
							| 27 |  | ovex |  | 
						
							| 28 |  | eqeq1 |  | 
						
							| 29 | 28 | rexbidv |  | 
						
							| 30 | 27 29 | elab |  | 
						
							| 31 | 26 30 | sylibr |  | 
						
							| 32 |  | elun2 |  | 
						
							| 33 | 31 32 | syl |  | 
						
							| 34 |  | ovex |  | 
						
							| 35 | 34 | snid |  | 
						
							| 36 | 35 | a1i |  | 
						
							| 37 | 14 33 36 | ssltsepcd |  | 
						
							| 38 | 3 2 | addscomd |  | 
						
							| 39 | 4 2 | addscomd |  | 
						
							| 40 | 37 38 39 | 3brtr4d |  |