| Step | Hyp | Ref | Expression | 
						
							| 1 |  | sshjococ.1 |  |-  A C_ ~H | 
						
							| 2 |  | sshjococ.2 |  |-  B C_ ~H | 
						
							| 3 |  | ococss |  |-  ( A C_ ~H -> A C_ ( _|_ ` ( _|_ ` A ) ) ) | 
						
							| 4 | 1 3 | ax-mp |  |-  A C_ ( _|_ ` ( _|_ ` A ) ) | 
						
							| 5 |  | ococss |  |-  ( B C_ ~H -> B C_ ( _|_ ` ( _|_ ` B ) ) ) | 
						
							| 6 | 2 5 | ax-mp |  |-  B C_ ( _|_ ` ( _|_ ` B ) ) | 
						
							| 7 |  | unss12 |  |-  ( ( A C_ ( _|_ ` ( _|_ ` A ) ) /\ B C_ ( _|_ ` ( _|_ ` B ) ) ) -> ( A u. B ) C_ ( ( _|_ ` ( _|_ ` A ) ) u. ( _|_ ` ( _|_ ` B ) ) ) ) | 
						
							| 8 | 4 6 7 | mp2an |  |-  ( A u. B ) C_ ( ( _|_ ` ( _|_ ` A ) ) u. ( _|_ ` ( _|_ ` B ) ) ) | 
						
							| 9 | 1 2 | unssi |  |-  ( A u. B ) C_ ~H | 
						
							| 10 |  | occl |  |-  ( A C_ ~H -> ( _|_ ` A ) e. CH ) | 
						
							| 11 | 1 10 | ax-mp |  |-  ( _|_ ` A ) e. CH | 
						
							| 12 | 11 | choccli |  |-  ( _|_ ` ( _|_ ` A ) ) e. CH | 
						
							| 13 | 12 | chssii |  |-  ( _|_ ` ( _|_ ` A ) ) C_ ~H | 
						
							| 14 |  | occl |  |-  ( B C_ ~H -> ( _|_ ` B ) e. CH ) | 
						
							| 15 | 2 14 | ax-mp |  |-  ( _|_ ` B ) e. CH | 
						
							| 16 | 15 | choccli |  |-  ( _|_ ` ( _|_ ` B ) ) e. CH | 
						
							| 17 | 16 | chssii |  |-  ( _|_ ` ( _|_ ` B ) ) C_ ~H | 
						
							| 18 | 13 17 | unssi |  |-  ( ( _|_ ` ( _|_ ` A ) ) u. ( _|_ ` ( _|_ ` B ) ) ) C_ ~H | 
						
							| 19 | 9 18 | occon2i |  |-  ( ( A u. B ) C_ ( ( _|_ ` ( _|_ ` A ) ) u. ( _|_ ` ( _|_ ` B ) ) ) -> ( _|_ ` ( _|_ ` ( A u. B ) ) ) C_ ( _|_ ` ( _|_ ` ( ( _|_ ` ( _|_ ` A ) ) u. ( _|_ ` ( _|_ ` B ) ) ) ) ) ) | 
						
							| 20 | 8 19 | ax-mp |  |-  ( _|_ ` ( _|_ ` ( A u. B ) ) ) C_ ( _|_ ` ( _|_ ` ( ( _|_ ` ( _|_ ` A ) ) u. ( _|_ ` ( _|_ ` B ) ) ) ) ) | 
						
							| 21 |  | sshjval |  |-  ( ( A C_ ~H /\ B C_ ~H ) -> ( A vH B ) = ( _|_ ` ( _|_ ` ( A u. B ) ) ) ) | 
						
							| 22 | 1 2 21 | mp2an |  |-  ( A vH B ) = ( _|_ ` ( _|_ ` ( A u. B ) ) ) | 
						
							| 23 | 12 16 | chjvali |  |-  ( ( _|_ ` ( _|_ ` A ) ) vH ( _|_ ` ( _|_ ` B ) ) ) = ( _|_ ` ( _|_ ` ( ( _|_ ` ( _|_ ` A ) ) u. ( _|_ ` ( _|_ ` B ) ) ) ) ) | 
						
							| 24 | 20 22 23 | 3sstr4i |  |-  ( A vH B ) C_ ( ( _|_ ` ( _|_ ` A ) ) vH ( _|_ ` ( _|_ ` B ) ) ) | 
						
							| 25 |  | ssun1 |  |-  A C_ ( A u. B ) | 
						
							| 26 |  | ococss |  |-  ( ( A u. B ) C_ ~H -> ( A u. B ) C_ ( _|_ ` ( _|_ ` ( A u. B ) ) ) ) | 
						
							| 27 | 9 26 | ax-mp |  |-  ( A u. B ) C_ ( _|_ ` ( _|_ ` ( A u. B ) ) ) | 
						
							| 28 | 25 27 | sstri |  |-  A C_ ( _|_ ` ( _|_ ` ( A u. B ) ) ) | 
						
							| 29 | 28 22 | sseqtrri |  |-  A C_ ( A vH B ) | 
						
							| 30 |  | sshjcl |  |-  ( ( A C_ ~H /\ B C_ ~H ) -> ( A vH B ) e. CH ) | 
						
							| 31 | 1 2 30 | mp2an |  |-  ( A vH B ) e. CH | 
						
							| 32 | 31 | chssii |  |-  ( A vH B ) C_ ~H | 
						
							| 33 | 1 32 | occon2i |  |-  ( A C_ ( A vH B ) -> ( _|_ ` ( _|_ ` A ) ) C_ ( _|_ ` ( _|_ ` ( A vH B ) ) ) ) | 
						
							| 34 | 29 33 | ax-mp |  |-  ( _|_ ` ( _|_ ` A ) ) C_ ( _|_ ` ( _|_ ` ( A vH B ) ) ) | 
						
							| 35 |  | ssun2 |  |-  B C_ ( A u. B ) | 
						
							| 36 | 35 27 | sstri |  |-  B C_ ( _|_ ` ( _|_ ` ( A u. B ) ) ) | 
						
							| 37 | 36 22 | sseqtrri |  |-  B C_ ( A vH B ) | 
						
							| 38 | 2 32 | occon2i |  |-  ( B C_ ( A vH B ) -> ( _|_ ` ( _|_ ` B ) ) C_ ( _|_ ` ( _|_ ` ( A vH B ) ) ) ) | 
						
							| 39 | 37 38 | ax-mp |  |-  ( _|_ ` ( _|_ ` B ) ) C_ ( _|_ ` ( _|_ ` ( A vH B ) ) ) | 
						
							| 40 | 31 | choccli |  |-  ( _|_ ` ( A vH B ) ) e. CH | 
						
							| 41 | 40 | choccli |  |-  ( _|_ ` ( _|_ ` ( A vH B ) ) ) e. CH | 
						
							| 42 | 12 16 41 | chlubii |  |-  ( ( ( _|_ ` ( _|_ ` A ) ) C_ ( _|_ ` ( _|_ ` ( A vH B ) ) ) /\ ( _|_ ` ( _|_ ` B ) ) C_ ( _|_ ` ( _|_ ` ( A vH B ) ) ) ) -> ( ( _|_ ` ( _|_ ` A ) ) vH ( _|_ ` ( _|_ ` B ) ) ) C_ ( _|_ ` ( _|_ ` ( A vH B ) ) ) ) | 
						
							| 43 | 34 39 42 | mp2an |  |-  ( ( _|_ ` ( _|_ ` A ) ) vH ( _|_ ` ( _|_ ` B ) ) ) C_ ( _|_ ` ( _|_ ` ( A vH B ) ) ) | 
						
							| 44 | 31 | ococi |  |-  ( _|_ ` ( _|_ ` ( A vH B ) ) ) = ( A vH B ) | 
						
							| 45 | 43 44 | sseqtri |  |-  ( ( _|_ ` ( _|_ ` A ) ) vH ( _|_ ` ( _|_ ` B ) ) ) C_ ( A vH B ) | 
						
							| 46 | 24 45 | eqssi |  |-  ( A vH B ) = ( ( _|_ ` ( _|_ ` A ) ) vH ( _|_ ` ( _|_ ` B ) ) ) |