| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 2zrng.e |  | 
						
							| 2 |  | 2zrngbas.r |  | 
						
							| 3 |  | 2zrngmmgm.1 |  | 
						
							| 4 |  | eqeq1 |  | 
						
							| 5 | 4 | rexbidv |  | 
						
							| 6 | 5 1 | elrab2 |  | 
						
							| 7 |  | eqeq1 |  | 
						
							| 8 | 7 | rexbidv |  | 
						
							| 9 | 8 1 | elrab2 |  | 
						
							| 10 |  | zmulcl |  | 
						
							| 11 | 10 | ad2ant2r |  | 
						
							| 12 |  | nfv |  | 
						
							| 13 |  | nfv |  | 
						
							| 14 |  | nfre1 |  | 
						
							| 15 | 13 14 | nfan |  | 
						
							| 16 |  | nfv |  | 
						
							| 17 | 15 16 | nfim |  | 
						
							| 18 | 12 17 | nfim |  | 
						
							| 19 |  | simpll |  | 
						
							| 20 |  | simpl |  | 
						
							| 21 |  | zmulcl |  | 
						
							| 22 | 19 20 21 | syl2an |  | 
						
							| 23 |  | oveq2 |  | 
						
							| 24 | 23 | eqeq2d |  | 
						
							| 25 | 24 | adantl |  | 
						
							| 26 |  | oveq1 |  | 
						
							| 27 | 26 | ad3antlr |  | 
						
							| 28 |  | 2cnd |  | 
						
							| 29 |  | zcn |  | 
						
							| 30 | 29 | ad3antrrr |  | 
						
							| 31 |  | zcn |  | 
						
							| 32 | 31 | adantr |  | 
						
							| 33 | 32 | adantl |  | 
						
							| 34 | 28 30 33 | mulassd |  | 
						
							| 35 | 27 34 | eqtrd |  | 
						
							| 36 | 22 25 35 | rspcedvd |  | 
						
							| 37 | 36 | exp41 |  | 
						
							| 38 | 18 37 | rexlimi |  | 
						
							| 39 | 38 | impcom |  | 
						
							| 40 | 39 | imp |  | 
						
							| 41 |  | eqeq1 |  | 
						
							| 42 | 41 | rexbidv |  | 
						
							| 43 | 42 1 | elrab2 |  | 
						
							| 44 |  | oveq2 |  | 
						
							| 45 | 44 | eqeq2d |  | 
						
							| 46 | 45 | cbvrexvw |  | 
						
							| 47 | 46 | anbi2i |  | 
						
							| 48 | 43 47 | bitri |  | 
						
							| 49 | 11 40 48 | sylanbrc |  | 
						
							| 50 | 6 9 49 | syl2anb |  | 
						
							| 51 | 50 | rgen2 |  | 
						
							| 52 | 1 | 0even |  | 
						
							| 53 | 1 2 | 2zrngbas |  | 
						
							| 54 | 3 53 | mgpbas |  | 
						
							| 55 | 1 2 | 2zrngmul |  | 
						
							| 56 | 3 55 | mgpplusg |  | 
						
							| 57 | 54 56 | ismgmn0 |  | 
						
							| 58 | 52 57 | ax-mp |  | 
						
							| 59 | 51 58 | mpbir |  |