| Step | Hyp | Ref | Expression | 
						
							| 1 |  | omex |  | 
						
							| 2 |  | ovex |  | 
						
							| 3 | 1 2 | iunex |  | 
						
							| 4 |  | xp1st |  | 
						
							| 5 |  | peano2 |  | 
						
							| 6 | 4 5 | syl |  | 
						
							| 7 |  | xp2nd |  | 
						
							| 8 |  | fconst6g |  | 
						
							| 9 | 7 8 | syl |  | 
						
							| 10 | 9 | adantl |  | 
						
							| 11 |  | elmapg |  | 
						
							| 12 | 6 11 | sylan2 |  | 
						
							| 13 | 10 12 | mpbird |  | 
						
							| 14 |  | oveq2 |  | 
						
							| 15 | 14 | eliuni |  | 
						
							| 16 | 6 13 15 | syl2an2 |  | 
						
							| 17 | 16 | ex |  | 
						
							| 18 |  | nsuceq0 |  | 
						
							| 19 |  | fvex |  | 
						
							| 20 | 19 | snnz |  | 
						
							| 21 |  | xp11 |  | 
						
							| 22 | 18 20 21 | mp2an |  | 
						
							| 23 |  | xp1st |  | 
						
							| 24 |  | peano4 |  | 
						
							| 25 | 4 23 24 | syl2an |  | 
						
							| 26 |  | sneqbg |  | 
						
							| 27 | 19 26 | mp1i |  | 
						
							| 28 | 25 27 | anbi12d |  | 
						
							| 29 | 22 28 | bitrid |  | 
						
							| 30 |  | xpopth |  | 
						
							| 31 | 29 30 | bitrd |  | 
						
							| 32 | 31 | a1i |  | 
						
							| 33 | 17 32 | dom2d |  | 
						
							| 34 | 3 33 | mpi |  |