| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mdslmd.1 | ⊢ 𝐴  ∈   Cℋ | 
						
							| 2 |  | mdslmd.2 | ⊢ 𝐵  ∈   Cℋ | 
						
							| 3 |  | mdslmd.3 | ⊢ 𝐶  ∈   Cℋ | 
						
							| 4 |  | mdslmd.4 | ⊢ 𝐷  ∈   Cℋ | 
						
							| 5 | 3 4 | chjcli | ⊢ ( 𝐶  ∨ℋ  𝐷 )  ∈   Cℋ | 
						
							| 6 | 5 2 1 | chlej1i | ⊢ ( ( 𝐶  ∨ℋ  𝐷 )  ⊆  𝐵  →  ( ( 𝐶  ∨ℋ  𝐷 )  ∨ℋ  𝐴 )  ⊆  ( 𝐵  ∨ℋ  𝐴 ) ) | 
						
							| 7 | 3 4 1 | chjjdiri | ⊢ ( ( 𝐶  ∨ℋ  𝐷 )  ∨ℋ  𝐴 )  =  ( ( 𝐶  ∨ℋ  𝐴 )  ∨ℋ  ( 𝐷  ∨ℋ  𝐴 ) ) | 
						
							| 8 | 2 1 | chjcomi | ⊢ ( 𝐵  ∨ℋ  𝐴 )  =  ( 𝐴  ∨ℋ  𝐵 ) | 
						
							| 9 | 6 7 8 | 3sstr3g | ⊢ ( ( 𝐶  ∨ℋ  𝐷 )  ⊆  𝐵  →  ( ( 𝐶  ∨ℋ  𝐴 )  ∨ℋ  ( 𝐷  ∨ℋ  𝐴 ) )  ⊆  ( 𝐴  ∨ℋ  𝐵 ) ) | 
						
							| 10 | 9 | adantl | ⊢ ( ( ( 𝐴  ∩  𝐵 )  ⊆  ( 𝐶  ∩  𝐷 )  ∧  ( 𝐶  ∨ℋ  𝐷 )  ⊆  𝐵 )  →  ( ( 𝐶  ∨ℋ  𝐴 )  ∨ℋ  ( 𝐷  ∨ℋ  𝐴 ) )  ⊆  ( 𝐴  ∨ℋ  𝐵 ) ) | 
						
							| 11 | 1 3 | chub2i | ⊢ 𝐴  ⊆  ( 𝐶  ∨ℋ  𝐴 ) | 
						
							| 12 | 1 4 | chub2i | ⊢ 𝐴  ⊆  ( 𝐷  ∨ℋ  𝐴 ) | 
						
							| 13 | 11 12 | ssini | ⊢ 𝐴  ⊆  ( ( 𝐶  ∨ℋ  𝐴 )  ∩  ( 𝐷  ∨ℋ  𝐴 ) ) | 
						
							| 14 | 10 13 | jctil | ⊢ ( ( ( 𝐴  ∩  𝐵 )  ⊆  ( 𝐶  ∩  𝐷 )  ∧  ( 𝐶  ∨ℋ  𝐷 )  ⊆  𝐵 )  →  ( 𝐴  ⊆  ( ( 𝐶  ∨ℋ  𝐴 )  ∩  ( 𝐷  ∨ℋ  𝐴 ) )  ∧  ( ( 𝐶  ∨ℋ  𝐴 )  ∨ℋ  ( 𝐷  ∨ℋ  𝐴 ) )  ⊆  ( 𝐴  ∨ℋ  𝐵 ) ) ) | 
						
							| 15 | 3 1 | chjcli | ⊢ ( 𝐶  ∨ℋ  𝐴 )  ∈   Cℋ | 
						
							| 16 | 4 1 | chjcli | ⊢ ( 𝐷  ∨ℋ  𝐴 )  ∈   Cℋ | 
						
							| 17 | 1 2 15 16 | mdslmd1i | ⊢ ( ( ( 𝐴  𝑀ℋ  𝐵  ∧  𝐵  𝑀ℋ*  𝐴 )  ∧  ( 𝐴  ⊆  ( ( 𝐶  ∨ℋ  𝐴 )  ∩  ( 𝐷  ∨ℋ  𝐴 ) )  ∧  ( ( 𝐶  ∨ℋ  𝐴 )  ∨ℋ  ( 𝐷  ∨ℋ  𝐴 ) )  ⊆  ( 𝐴  ∨ℋ  𝐵 ) ) )  →  ( ( 𝐶  ∨ℋ  𝐴 )  𝑀ℋ  ( 𝐷  ∨ℋ  𝐴 )  ↔  ( ( 𝐶  ∨ℋ  𝐴 )  ∩  𝐵 )  𝑀ℋ  ( ( 𝐷  ∨ℋ  𝐴 )  ∩  𝐵 ) ) ) | 
						
							| 18 | 14 17 | sylan2 | ⊢ ( ( ( 𝐴  𝑀ℋ  𝐵  ∧  𝐵  𝑀ℋ*  𝐴 )  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  ( 𝐶  ∩  𝐷 )  ∧  ( 𝐶  ∨ℋ  𝐷 )  ⊆  𝐵 ) )  →  ( ( 𝐶  ∨ℋ  𝐴 )  𝑀ℋ  ( 𝐷  ∨ℋ  𝐴 )  ↔  ( ( 𝐶  ∨ℋ  𝐴 )  ∩  𝐵 )  𝑀ℋ  ( ( 𝐷  ∨ℋ  𝐴 )  ∩  𝐵 ) ) ) | 
						
							| 19 |  | id | ⊢ ( 𝐴  𝑀ℋ  𝐵  →  𝐴  𝑀ℋ  𝐵 ) | 
						
							| 20 |  | inss1 | ⊢ ( 𝐶  ∩  𝐷 )  ⊆  𝐶 | 
						
							| 21 |  | sstr | ⊢ ( ( ( 𝐴  ∩  𝐵 )  ⊆  ( 𝐶  ∩  𝐷 )  ∧  ( 𝐶  ∩  𝐷 )  ⊆  𝐶 )  →  ( 𝐴  ∩  𝐵 )  ⊆  𝐶 ) | 
						
							| 22 | 20 21 | mpan2 | ⊢ ( ( 𝐴  ∩  𝐵 )  ⊆  ( 𝐶  ∩  𝐷 )  →  ( 𝐴  ∩  𝐵 )  ⊆  𝐶 ) | 
						
							| 23 | 3 4 | chub1i | ⊢ 𝐶  ⊆  ( 𝐶  ∨ℋ  𝐷 ) | 
						
							| 24 |  | sstr | ⊢ ( ( 𝐶  ⊆  ( 𝐶  ∨ℋ  𝐷 )  ∧  ( 𝐶  ∨ℋ  𝐷 )  ⊆  𝐵 )  →  𝐶  ⊆  𝐵 ) | 
						
							| 25 | 23 24 | mpan | ⊢ ( ( 𝐶  ∨ℋ  𝐷 )  ⊆  𝐵  →  𝐶  ⊆  𝐵 ) | 
						
							| 26 | 1 2 3 | 3pm3.2i | ⊢ ( 𝐴  ∈   Cℋ   ∧  𝐵  ∈   Cℋ   ∧  𝐶  ∈   Cℋ  ) | 
						
							| 27 |  | mdsl3 | ⊢ ( ( ( 𝐴  ∈   Cℋ   ∧  𝐵  ∈   Cℋ   ∧  𝐶  ∈   Cℋ  )  ∧  ( 𝐴  𝑀ℋ  𝐵  ∧  ( 𝐴  ∩  𝐵 )  ⊆  𝐶  ∧  𝐶  ⊆  𝐵 ) )  →  ( ( 𝐶  ∨ℋ  𝐴 )  ∩  𝐵 )  =  𝐶 ) | 
						
							| 28 | 26 27 | mpan | ⊢ ( ( 𝐴  𝑀ℋ  𝐵  ∧  ( 𝐴  ∩  𝐵 )  ⊆  𝐶  ∧  𝐶  ⊆  𝐵 )  →  ( ( 𝐶  ∨ℋ  𝐴 )  ∩  𝐵 )  =  𝐶 ) | 
						
							| 29 | 19 22 25 28 | syl3an | ⊢ ( ( 𝐴  𝑀ℋ  𝐵  ∧  ( 𝐴  ∩  𝐵 )  ⊆  ( 𝐶  ∩  𝐷 )  ∧  ( 𝐶  ∨ℋ  𝐷 )  ⊆  𝐵 )  →  ( ( 𝐶  ∨ℋ  𝐴 )  ∩  𝐵 )  =  𝐶 ) | 
						
							| 30 |  | inss2 | ⊢ ( 𝐶  ∩  𝐷 )  ⊆  𝐷 | 
						
							| 31 |  | sstr | ⊢ ( ( ( 𝐴  ∩  𝐵 )  ⊆  ( 𝐶  ∩  𝐷 )  ∧  ( 𝐶  ∩  𝐷 )  ⊆  𝐷 )  →  ( 𝐴  ∩  𝐵 )  ⊆  𝐷 ) | 
						
							| 32 | 30 31 | mpan2 | ⊢ ( ( 𝐴  ∩  𝐵 )  ⊆  ( 𝐶  ∩  𝐷 )  →  ( 𝐴  ∩  𝐵 )  ⊆  𝐷 ) | 
						
							| 33 | 4 3 | chub2i | ⊢ 𝐷  ⊆  ( 𝐶  ∨ℋ  𝐷 ) | 
						
							| 34 |  | sstr | ⊢ ( ( 𝐷  ⊆  ( 𝐶  ∨ℋ  𝐷 )  ∧  ( 𝐶  ∨ℋ  𝐷 )  ⊆  𝐵 )  →  𝐷  ⊆  𝐵 ) | 
						
							| 35 | 33 34 | mpan | ⊢ ( ( 𝐶  ∨ℋ  𝐷 )  ⊆  𝐵  →  𝐷  ⊆  𝐵 ) | 
						
							| 36 | 1 2 4 | 3pm3.2i | ⊢ ( 𝐴  ∈   Cℋ   ∧  𝐵  ∈   Cℋ   ∧  𝐷  ∈   Cℋ  ) | 
						
							| 37 |  | mdsl3 | ⊢ ( ( ( 𝐴  ∈   Cℋ   ∧  𝐵  ∈   Cℋ   ∧  𝐷  ∈   Cℋ  )  ∧  ( 𝐴  𝑀ℋ  𝐵  ∧  ( 𝐴  ∩  𝐵 )  ⊆  𝐷  ∧  𝐷  ⊆  𝐵 ) )  →  ( ( 𝐷  ∨ℋ  𝐴 )  ∩  𝐵 )  =  𝐷 ) | 
						
							| 38 | 36 37 | mpan | ⊢ ( ( 𝐴  𝑀ℋ  𝐵  ∧  ( 𝐴  ∩  𝐵 )  ⊆  𝐷  ∧  𝐷  ⊆  𝐵 )  →  ( ( 𝐷  ∨ℋ  𝐴 )  ∩  𝐵 )  =  𝐷 ) | 
						
							| 39 | 19 32 35 38 | syl3an | ⊢ ( ( 𝐴  𝑀ℋ  𝐵  ∧  ( 𝐴  ∩  𝐵 )  ⊆  ( 𝐶  ∩  𝐷 )  ∧  ( 𝐶  ∨ℋ  𝐷 )  ⊆  𝐵 )  →  ( ( 𝐷  ∨ℋ  𝐴 )  ∩  𝐵 )  =  𝐷 ) | 
						
							| 40 | 29 39 | breq12d | ⊢ ( ( 𝐴  𝑀ℋ  𝐵  ∧  ( 𝐴  ∩  𝐵 )  ⊆  ( 𝐶  ∩  𝐷 )  ∧  ( 𝐶  ∨ℋ  𝐷 )  ⊆  𝐵 )  →  ( ( ( 𝐶  ∨ℋ  𝐴 )  ∩  𝐵 )  𝑀ℋ  ( ( 𝐷  ∨ℋ  𝐴 )  ∩  𝐵 )  ↔  𝐶  𝑀ℋ  𝐷 ) ) | 
						
							| 41 | 40 | 3expb | ⊢ ( ( 𝐴  𝑀ℋ  𝐵  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  ( 𝐶  ∩  𝐷 )  ∧  ( 𝐶  ∨ℋ  𝐷 )  ⊆  𝐵 ) )  →  ( ( ( 𝐶  ∨ℋ  𝐴 )  ∩  𝐵 )  𝑀ℋ  ( ( 𝐷  ∨ℋ  𝐴 )  ∩  𝐵 )  ↔  𝐶  𝑀ℋ  𝐷 ) ) | 
						
							| 42 | 41 | adantlr | ⊢ ( ( ( 𝐴  𝑀ℋ  𝐵  ∧  𝐵  𝑀ℋ*  𝐴 )  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  ( 𝐶  ∩  𝐷 )  ∧  ( 𝐶  ∨ℋ  𝐷 )  ⊆  𝐵 ) )  →  ( ( ( 𝐶  ∨ℋ  𝐴 )  ∩  𝐵 )  𝑀ℋ  ( ( 𝐷  ∨ℋ  𝐴 )  ∩  𝐵 )  ↔  𝐶  𝑀ℋ  𝐷 ) ) | 
						
							| 43 | 18 42 | bitr2d | ⊢ ( ( ( 𝐴  𝑀ℋ  𝐵  ∧  𝐵  𝑀ℋ*  𝐴 )  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  ( 𝐶  ∩  𝐷 )  ∧  ( 𝐶  ∨ℋ  𝐷 )  ⊆  𝐵 ) )  →  ( 𝐶  𝑀ℋ  𝐷  ↔  ( 𝐶  ∨ℋ  𝐴 )  𝑀ℋ  ( 𝐷  ∨ℋ  𝐴 ) ) ) |