| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mulgnndir.b |  | 
						
							| 2 |  | mulgnndir.t |  | 
						
							| 3 |  | mulgnndir.p |  | 
						
							| 4 | 1 2 3 | mulgdirlem |  | 
						
							| 5 | 4 | 3expa |  | 
						
							| 6 |  | simpll |  | 
						
							| 7 |  | simpr2 |  | 
						
							| 8 | 7 | adantr |  | 
						
							| 9 | 8 | znegcld |  | 
						
							| 10 |  | simpr1 |  | 
						
							| 11 | 10 | adantr |  | 
						
							| 12 | 11 | znegcld |  | 
						
							| 13 |  | simplr3 |  | 
						
							| 14 | 11 | zcnd |  | 
						
							| 15 | 14 | negcld |  | 
						
							| 16 | 8 | zcnd |  | 
						
							| 17 | 16 | negcld |  | 
						
							| 18 | 14 16 | negdid |  | 
						
							| 19 | 15 17 18 | comraddd |  | 
						
							| 20 |  | simpr |  | 
						
							| 21 | 19 20 | eqeltrrd |  | 
						
							| 22 | 1 2 3 | mulgdirlem |  | 
						
							| 23 | 6 9 12 13 21 22 | syl131anc |  | 
						
							| 24 | 19 | oveq1d |  | 
						
							| 25 | 10 7 | zaddcld |  | 
						
							| 26 | 25 | adantr |  | 
						
							| 27 |  | eqid |  | 
						
							| 28 | 1 2 27 | mulgneg |  | 
						
							| 29 | 6 26 13 28 | syl3anc |  | 
						
							| 30 | 24 29 | eqtr3d |  | 
						
							| 31 | 1 2 27 | mulgneg |  | 
						
							| 32 | 6 8 13 31 | syl3anc |  | 
						
							| 33 | 1 2 27 | mulgneg |  | 
						
							| 34 | 6 11 13 33 | syl3anc |  | 
						
							| 35 | 32 34 | oveq12d |  | 
						
							| 36 | 1 2 | mulgcl |  | 
						
							| 37 | 6 11 13 36 | syl3anc |  | 
						
							| 38 | 1 2 | mulgcl |  | 
						
							| 39 | 6 8 13 38 | syl3anc |  | 
						
							| 40 | 1 3 27 | grpinvadd |  | 
						
							| 41 | 6 37 39 40 | syl3anc |  | 
						
							| 42 | 35 41 | eqtr4d |  | 
						
							| 43 | 23 30 42 | 3eqtr3d |  | 
						
							| 44 | 43 | fveq2d |  | 
						
							| 45 | 1 2 | mulgcl |  | 
						
							| 46 | 6 26 13 45 | syl3anc |  | 
						
							| 47 | 1 27 | grpinvinv |  | 
						
							| 48 | 6 46 47 | syl2anc |  | 
						
							| 49 | 1 3 | grpcl |  | 
						
							| 50 | 6 37 39 49 | syl3anc |  | 
						
							| 51 | 1 27 | grpinvinv |  | 
						
							| 52 | 6 50 51 | syl2anc |  | 
						
							| 53 | 44 48 52 | 3eqtr3d |  | 
						
							| 54 |  | elznn0 |  | 
						
							| 55 | 54 | simprbi |  | 
						
							| 56 | 25 55 | syl |  | 
						
							| 57 | 5 53 56 | mpjaodan |  |