| Step | Hyp | Ref | Expression | 
						
							| 1 |  | sumdmdi.1 |  |-  A e. CH | 
						
							| 2 |  | sumdmdi.2 |  |-  B e. CH | 
						
							| 3 | 1 2 | dmdbr6ati |  |-  ( A MH* B <-> A. x e. HAtoms ( ( A vH B ) i^i x ) = ( ( ( ( x vH B ) i^i A ) vH B ) i^i x ) ) | 
						
							| 4 |  | inss1 |  |-  ( ( ( ( x vH B ) i^i A ) vH B ) i^i x ) C_ ( ( ( x vH B ) i^i A ) vH B ) | 
						
							| 5 |  | sseq1 |  |-  ( ( ( A vH B ) i^i x ) = ( ( ( ( x vH B ) i^i A ) vH B ) i^i x ) -> ( ( ( A vH B ) i^i x ) C_ ( ( ( x vH B ) i^i A ) vH B ) <-> ( ( ( ( x vH B ) i^i A ) vH B ) i^i x ) C_ ( ( ( x vH B ) i^i A ) vH B ) ) ) | 
						
							| 6 | 4 5 | mpbiri |  |-  ( ( ( A vH B ) i^i x ) = ( ( ( ( x vH B ) i^i A ) vH B ) i^i x ) -> ( ( A vH B ) i^i x ) C_ ( ( ( x vH B ) i^i A ) vH B ) ) | 
						
							| 7 | 6 | ralimi |  |-  ( A. x e. HAtoms ( ( A vH B ) i^i x ) = ( ( ( ( x vH B ) i^i A ) vH B ) i^i x ) -> A. x e. HAtoms ( ( A vH B ) i^i x ) C_ ( ( ( x vH B ) i^i A ) vH B ) ) | 
						
							| 8 | 3 7 | sylbi |  |-  ( A MH* B -> A. x e. HAtoms ( ( A vH B ) i^i x ) C_ ( ( ( x vH B ) i^i A ) vH B ) ) | 
						
							| 9 |  | sseqin2 |  |-  ( x C_ ( A vH B ) <-> ( ( A vH B ) i^i x ) = x ) | 
						
							| 10 | 9 | biimpi |  |-  ( x C_ ( A vH B ) -> ( ( A vH B ) i^i x ) = x ) | 
						
							| 11 | 10 | sseq1d |  |-  ( x C_ ( A vH B ) -> ( ( ( A vH B ) i^i x ) C_ ( ( ( x vH B ) i^i A ) vH B ) <-> x C_ ( ( ( x vH B ) i^i A ) vH B ) ) ) | 
						
							| 12 | 11 | biimpcd |  |-  ( ( ( A vH B ) i^i x ) C_ ( ( ( x vH B ) i^i A ) vH B ) -> ( x C_ ( A vH B ) -> x C_ ( ( ( x vH B ) i^i A ) vH B ) ) ) | 
						
							| 13 | 12 | ralimi |  |-  ( A. x e. HAtoms ( ( A vH B ) i^i x ) C_ ( ( ( x vH B ) i^i A ) vH B ) -> A. x e. HAtoms ( x C_ ( A vH B ) -> x C_ ( ( ( x vH B ) i^i A ) vH B ) ) ) | 
						
							| 14 | 1 2 | dmdbr5ati |  |-  ( A MH* B <-> A. x e. HAtoms ( x C_ ( A vH B ) -> x C_ ( ( ( x vH B ) i^i A ) vH B ) ) ) | 
						
							| 15 | 13 14 | sylibr |  |-  ( A. x e. HAtoms ( ( A vH B ) i^i x ) C_ ( ( ( x vH B ) i^i A ) vH B ) -> A MH* B ) | 
						
							| 16 | 8 15 | impbii |  |-  ( A MH* B <-> A. x e. HAtoms ( ( A vH B ) i^i x ) C_ ( ( ( x vH B ) i^i A ) vH B ) ) |