| Step | Hyp | Ref | Expression | 
						
							| 1 |  | leatom.b |  | 
						
							| 2 |  | leatom.l |  | 
						
							| 3 |  | leatom.z |  | 
						
							| 4 |  | leatom.a |  | 
						
							| 5 | 1 2 3 | op0le |  | 
						
							| 6 | 5 | 3adant3 |  | 
						
							| 7 | 6 | biantrurd |  | 
						
							| 8 |  | opposet |  | 
						
							| 9 | 8 | 3ad2ant1 |  | 
						
							| 10 | 1 3 | op0cl |  | 
						
							| 11 | 1 4 | atbase |  | 
						
							| 12 |  | id |  | 
						
							| 13 | 10 11 12 | 3anim123i |  | 
						
							| 14 | 13 | 3com23 |  | 
						
							| 15 |  | eqid |  | 
						
							| 16 | 3 15 4 | atcvr0 |  | 
						
							| 17 | 16 | 3adant2 |  | 
						
							| 18 | 1 2 15 | cvrnbtwn4 |  | 
						
							| 19 | 9 14 17 18 | syl3anc |  | 
						
							| 20 |  | eqcom |  | 
						
							| 21 | 20 | orbi1i |  | 
						
							| 22 | 19 21 | bitrdi |  | 
						
							| 23 | 7 22 | bitrd |  | 
						
							| 24 |  | orcom |  | 
						
							| 25 | 23 24 | bitrdi |  |