| Step | Hyp | Ref | Expression | 
						
							| 1 |  | symgfcoeu.g |  | 
						
							| 2 |  | eqid |  | 
						
							| 3 |  | eqid |  | 
						
							| 4 | 2 1 3 | symginv |  | 
						
							| 5 | 4 | 3ad2ant2 |  | 
						
							| 6 | 2 | symggrp |  | 
						
							| 7 | 6 | 3ad2ant1 |  | 
						
							| 8 |  | simp2 |  | 
						
							| 9 | 1 3 | grpinvcl |  | 
						
							| 10 | 7 8 9 | syl2anc |  | 
						
							| 11 | 5 10 | eqeltrrd |  | 
						
							| 12 |  | simp3 |  | 
						
							| 13 |  | eqid |  | 
						
							| 14 | 2 1 13 | symgov |  | 
						
							| 15 | 2 1 13 | symgcl |  | 
						
							| 16 | 14 15 | eqeltrrd |  | 
						
							| 17 | 11 12 16 | syl2anc |  | 
						
							| 18 |  | coass |  | 
						
							| 19 | 2 1 | symgbasf1o |  | 
						
							| 20 |  | f1ococnv2 |  | 
						
							| 21 | 8 19 20 | 3syl |  | 
						
							| 22 | 21 | coeq1d |  | 
						
							| 23 | 18 22 | eqtr3id |  | 
						
							| 24 | 2 1 | symgbasf1o |  | 
						
							| 25 |  | f1of |  | 
						
							| 26 |  | fcoi2 |  | 
						
							| 27 | 12 24 25 26 | 4syl |  | 
						
							| 28 | 23 27 | eqtr2d |  | 
						
							| 29 |  | simpr |  | 
						
							| 30 | 29 | coeq2d |  | 
						
							| 31 |  | coass |  | 
						
							| 32 |  | f1ococnv1 |  | 
						
							| 33 | 8 19 32 | 3syl |  | 
						
							| 34 | 33 | coeq1d |  | 
						
							| 35 | 34 | ad2antrr |  | 
						
							| 36 | 31 35 | eqtr3id |  | 
						
							| 37 |  | simplr |  | 
						
							| 38 | 2 1 | symgbasf1o |  | 
						
							| 39 |  | f1of |  | 
						
							| 40 |  | fcoi2 |  | 
						
							| 41 | 37 38 39 40 | 4syl |  | 
						
							| 42 | 30 36 41 | 3eqtrrd |  | 
						
							| 43 | 42 | ex |  | 
						
							| 44 | 43 | ralrimiva |  | 
						
							| 45 |  | coeq2 |  | 
						
							| 46 | 45 | eqeq2d |  | 
						
							| 47 | 46 | eqreu |  | 
						
							| 48 | 17 28 44 47 | syl3anc |  |