| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							pjoml2.1 | 
							 |-  A e. CH  | 
						
						
							| 2 | 
							
								
							 | 
							pjoml2.2 | 
							 |-  B e. CH  | 
						
						
							| 3 | 
							
								1
							 | 
							choccli | 
							 |-  ( _|_ ` A ) e. CH  | 
						
						
							| 4 | 
							
								2
							 | 
							choccli | 
							 |-  ( _|_ ` B ) e. CH  | 
						
						
							| 5 | 
							
								3 4
							 | 
							pjoml2i | 
							 |-  ( ( _|_ ` A ) C_ ( _|_ ` B ) -> ( ( _|_ ` A ) vH ( ( _|_ ` ( _|_ ` A ) ) i^i ( _|_ ` B ) ) ) = ( _|_ ` B ) )  | 
						
						
							| 6 | 
							
								2 1
							 | 
							chsscon3i | 
							 |-  ( B C_ A <-> ( _|_ ` A ) C_ ( _|_ ` B ) )  | 
						
						
							| 7 | 
							
								
							 | 
							eqcom | 
							 |-  ( ( _|_ ` ( ( _|_ ` A ) vH ( ( _|_ ` ( _|_ ` A ) ) i^i ( _|_ ` B ) ) ) ) = B <-> B = ( _|_ ` ( ( _|_ ` A ) vH ( ( _|_ ` ( _|_ ` A ) ) i^i ( _|_ ` B ) ) ) ) )  | 
						
						
							| 8 | 
							
								3
							 | 
							choccli | 
							 |-  ( _|_ ` ( _|_ ` A ) ) e. CH  | 
						
						
							| 9 | 
							
								8 4
							 | 
							chincli | 
							 |-  ( ( _|_ ` ( _|_ ` A ) ) i^i ( _|_ ` B ) ) e. CH  | 
						
						
							| 10 | 
							
								1 9
							 | 
							chdmj2i | 
							 |-  ( _|_ ` ( ( _|_ ` A ) vH ( ( _|_ ` ( _|_ ` A ) ) i^i ( _|_ ` B ) ) ) ) = ( A i^i ( _|_ ` ( ( _|_ ` ( _|_ ` A ) ) i^i ( _|_ ` B ) ) ) )  | 
						
						
							| 11 | 
							
								3 2
							 | 
							chdmm4i | 
							 |-  ( _|_ ` ( ( _|_ ` ( _|_ ` A ) ) i^i ( _|_ ` B ) ) ) = ( ( _|_ ` A ) vH B )  | 
						
						
							| 12 | 
							
								11
							 | 
							ineq2i | 
							 |-  ( A i^i ( _|_ ` ( ( _|_ ` ( _|_ ` A ) ) i^i ( _|_ ` B ) ) ) ) = ( A i^i ( ( _|_ ` A ) vH B ) )  | 
						
						
							| 13 | 
							
								10 12
							 | 
							eqtri | 
							 |-  ( _|_ ` ( ( _|_ ` A ) vH ( ( _|_ ` ( _|_ ` A ) ) i^i ( _|_ ` B ) ) ) ) = ( A i^i ( ( _|_ ` A ) vH B ) )  | 
						
						
							| 14 | 
							
								13
							 | 
							eqeq1i | 
							 |-  ( ( _|_ ` ( ( _|_ ` A ) vH ( ( _|_ ` ( _|_ ` A ) ) i^i ( _|_ ` B ) ) ) ) = B <-> ( A i^i ( ( _|_ ` A ) vH B ) ) = B )  | 
						
						
							| 15 | 
							
								3 9
							 | 
							chjcli | 
							 |-  ( ( _|_ ` A ) vH ( ( _|_ ` ( _|_ ` A ) ) i^i ( _|_ ` B ) ) ) e. CH  | 
						
						
							| 16 | 
							
								2 15
							 | 
							chcon2i | 
							 |-  ( B = ( _|_ ` ( ( _|_ ` A ) vH ( ( _|_ ` ( _|_ ` A ) ) i^i ( _|_ ` B ) ) ) ) <-> ( ( _|_ ` A ) vH ( ( _|_ ` ( _|_ ` A ) ) i^i ( _|_ ` B ) ) ) = ( _|_ ` B ) )  | 
						
						
							| 17 | 
							
								7 14 16
							 | 
							3bitr3i | 
							 |-  ( ( A i^i ( ( _|_ ` A ) vH B ) ) = B <-> ( ( _|_ ` A ) vH ( ( _|_ ` ( _|_ ` A ) ) i^i ( _|_ ` B ) ) ) = ( _|_ ` B ) )  | 
						
						
							| 18 | 
							
								5 6 17
							 | 
							3imtr4i | 
							 |-  ( B C_ A -> ( A i^i ( ( _|_ ` A ) vH B ) ) = B )  |