| Step | Hyp | Ref | Expression | 
						
							| 1 |  | csmdsym.1 | ⊢ 𝐴  ∈   Cℋ | 
						
							| 2 |  | csmdsym.2 | ⊢ 𝐵  ∈   Cℋ | 
						
							| 3 |  | incom | ⊢ ( 𝐴  ∩  𝐵 )  =  ( 𝐵  ∩  𝐴 ) | 
						
							| 4 | 3 | sseq1i | ⊢ ( ( 𝐴  ∩  𝐵 )  ⊆  𝑥  ↔  ( 𝐵  ∩  𝐴 )  ⊆  𝑥 ) | 
						
							| 5 | 4 | biimpri | ⊢ ( ( 𝐵  ∩  𝐴 )  ⊆  𝑥  →  ( 𝐴  ∩  𝐵 )  ⊆  𝑥 ) | 
						
							| 6 |  | chjcom | ⊢ ( ( 𝑥  ∈   Cℋ   ∧  𝐵  ∈   Cℋ  )  →  ( 𝑥  ∨ℋ  𝐵 )  =  ( 𝐵  ∨ℋ  𝑥 ) ) | 
						
							| 7 | 2 6 | mpan2 | ⊢ ( 𝑥  ∈   Cℋ   →  ( 𝑥  ∨ℋ  𝐵 )  =  ( 𝐵  ∨ℋ  𝑥 ) ) | 
						
							| 8 | 7 | ineq1d | ⊢ ( 𝑥  ∈   Cℋ   →  ( ( 𝑥  ∨ℋ  𝐵 )  ∩  𝐴 )  =  ( ( 𝐵  ∨ℋ  𝑥 )  ∩  𝐴 ) ) | 
						
							| 9 |  | incom | ⊢ ( ( 𝐵  ∨ℋ  𝑥 )  ∩  𝐴 )  =  ( 𝐴  ∩  ( 𝐵  ∨ℋ  𝑥 ) ) | 
						
							| 10 | 8 9 | eqtrdi | ⊢ ( 𝑥  ∈   Cℋ   →  ( ( 𝑥  ∨ℋ  𝐵 )  ∩  𝐴 )  =  ( 𝐴  ∩  ( 𝐵  ∨ℋ  𝑥 ) ) ) | 
						
							| 11 | 10 | ad2antlr | ⊢ ( ( ( ( ∀ 𝑐  ∈   Cℋ  ( 𝑐  𝑀ℋ  𝐵  →  𝐵  𝑀ℋ*  𝑐 )  ∧  𝐴  𝑀ℋ  𝐵 )  ∧  𝑥  ∈   Cℋ  )  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝑥  ∧  𝑥  ⊆  𝐴 ) )  →  ( ( 𝑥  ∨ℋ  𝐵 )  ∩  𝐴 )  =  ( 𝐴  ∩  ( 𝐵  ∨ℋ  𝑥 ) ) ) | 
						
							| 12 | 2 | a1i | ⊢ ( 𝑥  ∈   Cℋ   →  𝐵  ∈   Cℋ  ) | 
						
							| 13 |  | id | ⊢ ( 𝑥  ∈   Cℋ   →  𝑥  ∈   Cℋ  ) | 
						
							| 14 | 1 | a1i | ⊢ ( 𝑥  ∈   Cℋ   →  𝐴  ∈   Cℋ  ) | 
						
							| 15 | 12 13 14 | 3jca | ⊢ ( 𝑥  ∈   Cℋ   →  ( 𝐵  ∈   Cℋ   ∧  𝑥  ∈   Cℋ   ∧  𝐴  ∈   Cℋ  ) ) | 
						
							| 16 | 15 | ad2antlr | ⊢ ( ( ( ( ∀ 𝑐  ∈   Cℋ  ( 𝑐  𝑀ℋ  𝐵  →  𝐵  𝑀ℋ*  𝑐 )  ∧  𝐴  𝑀ℋ  𝐵 )  ∧  𝑥  ∈   Cℋ  )  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝑥  ∧  𝑥  ⊆  𝐴 ) )  →  ( 𝐵  ∈   Cℋ   ∧  𝑥  ∈   Cℋ   ∧  𝐴  ∈   Cℋ  ) ) | 
						
							| 17 |  | inss2 | ⊢ ( 𝐴  ∩  𝐵 )  ⊆  𝐵 | 
						
							| 18 |  | ssid | ⊢ 𝐵  ⊆  𝐵 | 
						
							| 19 | 17 18 | pm3.2i | ⊢ ( ( 𝐴  ∩  𝐵 )  ⊆  𝐵  ∧  𝐵  ⊆  𝐵 ) | 
						
							| 20 |  | sseq2 | ⊢ ( 𝑥  =  if ( 𝑥  ∈   Cℋ  ,  𝑥 ,  0ℋ )  →  ( ( 𝐴  ∩  𝐵 )  ⊆  𝑥  ↔  ( 𝐴  ∩  𝐵 )  ⊆  if ( 𝑥  ∈   Cℋ  ,  𝑥 ,  0ℋ ) ) ) | 
						
							| 21 |  | sseq1 | ⊢ ( 𝑥  =  if ( 𝑥  ∈   Cℋ  ,  𝑥 ,  0ℋ )  →  ( 𝑥  ⊆  𝐴  ↔  if ( 𝑥  ∈   Cℋ  ,  𝑥 ,  0ℋ )  ⊆  𝐴 ) ) | 
						
							| 22 | 20 21 | anbi12d | ⊢ ( 𝑥  =  if ( 𝑥  ∈   Cℋ  ,  𝑥 ,  0ℋ )  →  ( ( ( 𝐴  ∩  𝐵 )  ⊆  𝑥  ∧  𝑥  ⊆  𝐴 )  ↔  ( ( 𝐴  ∩  𝐵 )  ⊆  if ( 𝑥  ∈   Cℋ  ,  𝑥 ,  0ℋ )  ∧  if ( 𝑥  ∈   Cℋ  ,  𝑥 ,  0ℋ )  ⊆  𝐴 ) ) ) | 
						
							| 23 | 22 | 3anbi2d | ⊢ ( 𝑥  =  if ( 𝑥  ∈   Cℋ  ,  𝑥 ,  0ℋ )  →  ( ( 𝐴  𝑀ℋ  𝐵  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝑥  ∧  𝑥  ⊆  𝐴 )  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝐵  ∧  𝐵  ⊆  𝐵 ) )  ↔  ( 𝐴  𝑀ℋ  𝐵  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  if ( 𝑥  ∈   Cℋ  ,  𝑥 ,  0ℋ )  ∧  if ( 𝑥  ∈   Cℋ  ,  𝑥 ,  0ℋ )  ⊆  𝐴 )  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝐵  ∧  𝐵  ⊆  𝐵 ) ) ) ) | 
						
							| 24 |  | breq1 | ⊢ ( 𝑥  =  if ( 𝑥  ∈   Cℋ  ,  𝑥 ,  0ℋ )  →  ( 𝑥  𝑀ℋ  𝐵  ↔  if ( 𝑥  ∈   Cℋ  ,  𝑥 ,  0ℋ )  𝑀ℋ  𝐵 ) ) | 
						
							| 25 | 23 24 | imbi12d | ⊢ ( 𝑥  =  if ( 𝑥  ∈   Cℋ  ,  𝑥 ,  0ℋ )  →  ( ( ( 𝐴  𝑀ℋ  𝐵  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝑥  ∧  𝑥  ⊆  𝐴 )  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝐵  ∧  𝐵  ⊆  𝐵 ) )  →  𝑥  𝑀ℋ  𝐵 )  ↔  ( ( 𝐴  𝑀ℋ  𝐵  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  if ( 𝑥  ∈   Cℋ  ,  𝑥 ,  0ℋ )  ∧  if ( 𝑥  ∈   Cℋ  ,  𝑥 ,  0ℋ )  ⊆  𝐴 )  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝐵  ∧  𝐵  ⊆  𝐵 ) )  →  if ( 𝑥  ∈   Cℋ  ,  𝑥 ,  0ℋ )  𝑀ℋ  𝐵 ) ) ) | 
						
							| 26 |  | h0elch | ⊢ 0ℋ  ∈   Cℋ | 
						
							| 27 | 26 | elimel | ⊢ if ( 𝑥  ∈   Cℋ  ,  𝑥 ,  0ℋ )  ∈   Cℋ | 
						
							| 28 | 1 2 27 2 | mdslmd4i | ⊢ ( ( 𝐴  𝑀ℋ  𝐵  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  if ( 𝑥  ∈   Cℋ  ,  𝑥 ,  0ℋ )  ∧  if ( 𝑥  ∈   Cℋ  ,  𝑥 ,  0ℋ )  ⊆  𝐴 )  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝐵  ∧  𝐵  ⊆  𝐵 ) )  →  if ( 𝑥  ∈   Cℋ  ,  𝑥 ,  0ℋ )  𝑀ℋ  𝐵 ) | 
						
							| 29 | 25 28 | dedth | ⊢ ( 𝑥  ∈   Cℋ   →  ( ( 𝐴  𝑀ℋ  𝐵  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝑥  ∧  𝑥  ⊆  𝐴 )  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝐵  ∧  𝐵  ⊆  𝐵 ) )  →  𝑥  𝑀ℋ  𝐵 ) ) | 
						
							| 30 | 29 | com12 | ⊢ ( ( 𝐴  𝑀ℋ  𝐵  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝑥  ∧  𝑥  ⊆  𝐴 )  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝐵  ∧  𝐵  ⊆  𝐵 ) )  →  ( 𝑥  ∈   Cℋ   →  𝑥  𝑀ℋ  𝐵 ) ) | 
						
							| 31 | 19 30 | mp3an3 | ⊢ ( ( 𝐴  𝑀ℋ  𝐵  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝑥  ∧  𝑥  ⊆  𝐴 ) )  →  ( 𝑥  ∈   Cℋ   →  𝑥  𝑀ℋ  𝐵 ) ) | 
						
							| 32 | 31 | imp | ⊢ ( ( ( 𝐴  𝑀ℋ  𝐵  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝑥  ∧  𝑥  ⊆  𝐴 ) )  ∧  𝑥  ∈   Cℋ  )  →  𝑥  𝑀ℋ  𝐵 ) | 
						
							| 33 | 32 | an32s | ⊢ ( ( ( 𝐴  𝑀ℋ  𝐵  ∧  𝑥  ∈   Cℋ  )  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝑥  ∧  𝑥  ⊆  𝐴 ) )  →  𝑥  𝑀ℋ  𝐵 ) | 
						
							| 34 | 33 | adantlll | ⊢ ( ( ( ( ∀ 𝑐  ∈   Cℋ  ( 𝑐  𝑀ℋ  𝐵  →  𝐵  𝑀ℋ*  𝑐 )  ∧  𝐴  𝑀ℋ  𝐵 )  ∧  𝑥  ∈   Cℋ  )  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝑥  ∧  𝑥  ⊆  𝐴 ) )  →  𝑥  𝑀ℋ  𝐵 ) | 
						
							| 35 |  | breq1 | ⊢ ( 𝑐  =  𝑥  →  ( 𝑐  𝑀ℋ  𝐵  ↔  𝑥  𝑀ℋ  𝐵 ) ) | 
						
							| 36 |  | breq2 | ⊢ ( 𝑐  =  𝑥  →  ( 𝐵  𝑀ℋ*  𝑐  ↔  𝐵  𝑀ℋ*  𝑥 ) ) | 
						
							| 37 | 35 36 | imbi12d | ⊢ ( 𝑐  =  𝑥  →  ( ( 𝑐  𝑀ℋ  𝐵  →  𝐵  𝑀ℋ*  𝑐 )  ↔  ( 𝑥  𝑀ℋ  𝐵  →  𝐵  𝑀ℋ*  𝑥 ) ) ) | 
						
							| 38 | 37 | rspccva | ⊢ ( ( ∀ 𝑐  ∈   Cℋ  ( 𝑐  𝑀ℋ  𝐵  →  𝐵  𝑀ℋ*  𝑐 )  ∧  𝑥  ∈   Cℋ  )  →  ( 𝑥  𝑀ℋ  𝐵  →  𝐵  𝑀ℋ*  𝑥 ) ) | 
						
							| 39 | 38 | adantlr | ⊢ ( ( ( ∀ 𝑐  ∈   Cℋ  ( 𝑐  𝑀ℋ  𝐵  →  𝐵  𝑀ℋ*  𝑐 )  ∧  𝐴  𝑀ℋ  𝐵 )  ∧  𝑥  ∈   Cℋ  )  →  ( 𝑥  𝑀ℋ  𝐵  →  𝐵  𝑀ℋ*  𝑥 ) ) | 
						
							| 40 | 39 | adantr | ⊢ ( ( ( ( ∀ 𝑐  ∈   Cℋ  ( 𝑐  𝑀ℋ  𝐵  →  𝐵  𝑀ℋ*  𝑐 )  ∧  𝐴  𝑀ℋ  𝐵 )  ∧  𝑥  ∈   Cℋ  )  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝑥  ∧  𝑥  ⊆  𝐴 ) )  →  ( 𝑥  𝑀ℋ  𝐵  →  𝐵  𝑀ℋ*  𝑥 ) ) | 
						
							| 41 | 34 40 | mpd | ⊢ ( ( ( ( ∀ 𝑐  ∈   Cℋ  ( 𝑐  𝑀ℋ  𝐵  →  𝐵  𝑀ℋ*  𝑐 )  ∧  𝐴  𝑀ℋ  𝐵 )  ∧  𝑥  ∈   Cℋ  )  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝑥  ∧  𝑥  ⊆  𝐴 ) )  →  𝐵  𝑀ℋ*  𝑥 ) | 
						
							| 42 |  | simprr | ⊢ ( ( ( ( ∀ 𝑐  ∈   Cℋ  ( 𝑐  𝑀ℋ  𝐵  →  𝐵  𝑀ℋ*  𝑐 )  ∧  𝐴  𝑀ℋ  𝐵 )  ∧  𝑥  ∈   Cℋ  )  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝑥  ∧  𝑥  ⊆  𝐴 ) )  →  𝑥  ⊆  𝐴 ) | 
						
							| 43 |  | dmdi | ⊢ ( ( ( 𝐵  ∈   Cℋ   ∧  𝑥  ∈   Cℋ   ∧  𝐴  ∈   Cℋ  )  ∧  ( 𝐵  𝑀ℋ*  𝑥  ∧  𝑥  ⊆  𝐴 ) )  →  ( ( 𝐴  ∩  𝐵 )  ∨ℋ  𝑥 )  =  ( 𝐴  ∩  ( 𝐵  ∨ℋ  𝑥 ) ) ) | 
						
							| 44 | 16 41 42 43 | syl12anc | ⊢ ( ( ( ( ∀ 𝑐  ∈   Cℋ  ( 𝑐  𝑀ℋ  𝐵  →  𝐵  𝑀ℋ*  𝑐 )  ∧  𝐴  𝑀ℋ  𝐵 )  ∧  𝑥  ∈   Cℋ  )  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝑥  ∧  𝑥  ⊆  𝐴 ) )  →  ( ( 𝐴  ∩  𝐵 )  ∨ℋ  𝑥 )  =  ( 𝐴  ∩  ( 𝐵  ∨ℋ  𝑥 ) ) ) | 
						
							| 45 | 1 2 | chincli | ⊢ ( 𝐴  ∩  𝐵 )  ∈   Cℋ | 
						
							| 46 |  | chjcom | ⊢ ( ( ( 𝐴  ∩  𝐵 )  ∈   Cℋ   ∧  𝑥  ∈   Cℋ  )  →  ( ( 𝐴  ∩  𝐵 )  ∨ℋ  𝑥 )  =  ( 𝑥  ∨ℋ  ( 𝐴  ∩  𝐵 ) ) ) | 
						
							| 47 | 45 46 | mpan | ⊢ ( 𝑥  ∈   Cℋ   →  ( ( 𝐴  ∩  𝐵 )  ∨ℋ  𝑥 )  =  ( 𝑥  ∨ℋ  ( 𝐴  ∩  𝐵 ) ) ) | 
						
							| 48 | 3 | oveq2i | ⊢ ( 𝑥  ∨ℋ  ( 𝐴  ∩  𝐵 ) )  =  ( 𝑥  ∨ℋ  ( 𝐵  ∩  𝐴 ) ) | 
						
							| 49 | 47 48 | eqtrdi | ⊢ ( 𝑥  ∈   Cℋ   →  ( ( 𝐴  ∩  𝐵 )  ∨ℋ  𝑥 )  =  ( 𝑥  ∨ℋ  ( 𝐵  ∩  𝐴 ) ) ) | 
						
							| 50 | 49 | ad2antlr | ⊢ ( ( ( ( ∀ 𝑐  ∈   Cℋ  ( 𝑐  𝑀ℋ  𝐵  →  𝐵  𝑀ℋ*  𝑐 )  ∧  𝐴  𝑀ℋ  𝐵 )  ∧  𝑥  ∈   Cℋ  )  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝑥  ∧  𝑥  ⊆  𝐴 ) )  →  ( ( 𝐴  ∩  𝐵 )  ∨ℋ  𝑥 )  =  ( 𝑥  ∨ℋ  ( 𝐵  ∩  𝐴 ) ) ) | 
						
							| 51 | 11 44 50 | 3eqtr2d | ⊢ ( ( ( ( ∀ 𝑐  ∈   Cℋ  ( 𝑐  𝑀ℋ  𝐵  →  𝐵  𝑀ℋ*  𝑐 )  ∧  𝐴  𝑀ℋ  𝐵 )  ∧  𝑥  ∈   Cℋ  )  ∧  ( ( 𝐴  ∩  𝐵 )  ⊆  𝑥  ∧  𝑥  ⊆  𝐴 ) )  →  ( ( 𝑥  ∨ℋ  𝐵 )  ∩  𝐴 )  =  ( 𝑥  ∨ℋ  ( 𝐵  ∩  𝐴 ) ) ) | 
						
							| 52 | 51 | ex | ⊢ ( ( ( ∀ 𝑐  ∈   Cℋ  ( 𝑐  𝑀ℋ  𝐵  →  𝐵  𝑀ℋ*  𝑐 )  ∧  𝐴  𝑀ℋ  𝐵 )  ∧  𝑥  ∈   Cℋ  )  →  ( ( ( 𝐴  ∩  𝐵 )  ⊆  𝑥  ∧  𝑥  ⊆  𝐴 )  →  ( ( 𝑥  ∨ℋ  𝐵 )  ∩  𝐴 )  =  ( 𝑥  ∨ℋ  ( 𝐵  ∩  𝐴 ) ) ) ) | 
						
							| 53 | 5 52 | sylani | ⊢ ( ( ( ∀ 𝑐  ∈   Cℋ  ( 𝑐  𝑀ℋ  𝐵  →  𝐵  𝑀ℋ*  𝑐 )  ∧  𝐴  𝑀ℋ  𝐵 )  ∧  𝑥  ∈   Cℋ  )  →  ( ( ( 𝐵  ∩  𝐴 )  ⊆  𝑥  ∧  𝑥  ⊆  𝐴 )  →  ( ( 𝑥  ∨ℋ  𝐵 )  ∩  𝐴 )  =  ( 𝑥  ∨ℋ  ( 𝐵  ∩  𝐴 ) ) ) ) | 
						
							| 54 | 53 | ralrimiva | ⊢ ( ( ∀ 𝑐  ∈   Cℋ  ( 𝑐  𝑀ℋ  𝐵  →  𝐵  𝑀ℋ*  𝑐 )  ∧  𝐴  𝑀ℋ  𝐵 )  →  ∀ 𝑥  ∈   Cℋ  ( ( ( 𝐵  ∩  𝐴 )  ⊆  𝑥  ∧  𝑥  ⊆  𝐴 )  →  ( ( 𝑥  ∨ℋ  𝐵 )  ∩  𝐴 )  =  ( 𝑥  ∨ℋ  ( 𝐵  ∩  𝐴 ) ) ) ) | 
						
							| 55 | 2 1 | mdsl2bi | ⊢ ( 𝐵  𝑀ℋ  𝐴  ↔  ∀ 𝑥  ∈   Cℋ  ( ( ( 𝐵  ∩  𝐴 )  ⊆  𝑥  ∧  𝑥  ⊆  𝐴 )  →  ( ( 𝑥  ∨ℋ  𝐵 )  ∩  𝐴 )  =  ( 𝑥  ∨ℋ  ( 𝐵  ∩  𝐴 ) ) ) ) | 
						
							| 56 | 54 55 | sylibr | ⊢ ( ( ∀ 𝑐  ∈   Cℋ  ( 𝑐  𝑀ℋ  𝐵  →  𝐵  𝑀ℋ*  𝑐 )  ∧  𝐴  𝑀ℋ  𝐵 )  →  𝐵  𝑀ℋ  𝐴 ) |