| Step | Hyp | Ref | Expression | 
						
							| 1 |  | iscyg.1 |  | 
						
							| 2 |  | iscyg.2 |  | 
						
							| 3 | 1 2 | iscyg |  | 
						
							| 4 | 1 2 | mulgcl |  | 
						
							| 5 | 4 | 3expa |  | 
						
							| 6 | 5 | an32s |  | 
						
							| 7 | 6 | fmpttd |  | 
						
							| 8 |  | frn |  | 
						
							| 9 |  | eqss |  | 
						
							| 10 | 9 | baib |  | 
						
							| 11 | 7 8 10 | 3syl |  | 
						
							| 12 |  | dfss3 |  | 
						
							| 13 |  | eqid |  | 
						
							| 14 |  | ovex |  | 
						
							| 15 | 13 14 | elrnmpti |  | 
						
							| 16 | 15 | ralbii |  | 
						
							| 17 | 12 16 | bitri |  | 
						
							| 18 | 11 17 | bitrdi |  | 
						
							| 19 | 18 | rexbidva |  | 
						
							| 20 | 19 | pm5.32i |  | 
						
							| 21 | 3 20 | bitri |  |