| Step | Hyp | Ref | Expression | 
						
							| 1 |  | lautcnvle.b |  | 
						
							| 2 |  | lautcnvle.l |  | 
						
							| 3 |  | lautcnvle.i |  | 
						
							| 4 |  | simpl |  | 
						
							| 5 | 1 3 | laut1o |  | 
						
							| 6 | 5 | adantr |  | 
						
							| 7 |  | simprl |  | 
						
							| 8 |  | f1ocnvdm |  | 
						
							| 9 | 6 7 8 | syl2anc |  | 
						
							| 10 |  | simprr |  | 
						
							| 11 |  | f1ocnvdm |  | 
						
							| 12 | 6 10 11 | syl2anc |  | 
						
							| 13 | 1 2 3 | lautle |  | 
						
							| 14 | 4 9 12 13 | syl12anc |  | 
						
							| 15 |  | f1ocnvfv2 |  | 
						
							| 16 | 6 7 15 | syl2anc |  | 
						
							| 17 |  | f1ocnvfv2 |  | 
						
							| 18 | 6 10 17 | syl2anc |  | 
						
							| 19 | 16 18 | breq12d |  | 
						
							| 20 | 14 19 | bitr2d |  |