| Step | Hyp | Ref | Expression | 
						
							| 1 |  | large.1 | ⊢ 𝐴  ∈   Cℋ | 
						
							| 2 |  | ralnex | ⊢ ( ∀ 𝑓  ∈  States ¬  ( 𝑓 ‘ 𝐴 )  =  1  ↔  ¬  ∃ 𝑓  ∈  States ( 𝑓 ‘ 𝐴 )  =  1 ) | 
						
							| 3 |  | ax-1ne0 | ⊢ 1  ≠  0 | 
						
							| 4 | 3 | neii | ⊢ ¬  1  =  0 | 
						
							| 5 |  | st0 | ⊢ ( 𝑓  ∈  States  →  ( 𝑓 ‘ 0ℋ )  =  0 ) | 
						
							| 6 | 5 | eqeq1d | ⊢ ( 𝑓  ∈  States  →  ( ( 𝑓 ‘ 0ℋ )  =  1  ↔  0  =  1 ) ) | 
						
							| 7 |  | eqcom | ⊢ ( 0  =  1  ↔  1  =  0 ) | 
						
							| 8 | 6 7 | bitrdi | ⊢ ( 𝑓  ∈  States  →  ( ( 𝑓 ‘ 0ℋ )  =  1  ↔  1  =  0 ) ) | 
						
							| 9 | 4 8 | mtbiri | ⊢ ( 𝑓  ∈  States  →  ¬  ( 𝑓 ‘ 0ℋ )  =  1 ) | 
						
							| 10 |  | mtt | ⊢ ( ¬  ( 𝑓 ‘ 0ℋ )  =  1  →  ( ¬  ( 𝑓 ‘ 𝐴 )  =  1  ↔  ( ( 𝑓 ‘ 𝐴 )  =  1  →  ( 𝑓 ‘ 0ℋ )  =  1 ) ) ) | 
						
							| 11 | 9 10 | syl | ⊢ ( 𝑓  ∈  States  →  ( ¬  ( 𝑓 ‘ 𝐴 )  =  1  ↔  ( ( 𝑓 ‘ 𝐴 )  =  1  →  ( 𝑓 ‘ 0ℋ )  =  1 ) ) ) | 
						
							| 12 | 11 | ralbiia | ⊢ ( ∀ 𝑓  ∈  States ¬  ( 𝑓 ‘ 𝐴 )  =  1  ↔  ∀ 𝑓  ∈  States ( ( 𝑓 ‘ 𝐴 )  =  1  →  ( 𝑓 ‘ 0ℋ )  =  1 ) ) | 
						
							| 13 |  | h0elch | ⊢ 0ℋ  ∈   Cℋ | 
						
							| 14 | 1 13 | strb | ⊢ ( ∀ 𝑓  ∈  States ( ( 𝑓 ‘ 𝐴 )  =  1  →  ( 𝑓 ‘ 0ℋ )  =  1 )  ↔  𝐴  ⊆  0ℋ ) | 
						
							| 15 | 1 | chle0i | ⊢ ( 𝐴  ⊆  0ℋ  ↔  𝐴  =  0ℋ ) | 
						
							| 16 | 12 14 15 | 3bitri | ⊢ ( ∀ 𝑓  ∈  States ¬  ( 𝑓 ‘ 𝐴 )  =  1  ↔  𝐴  =  0ℋ ) | 
						
							| 17 | 2 16 | bitr3i | ⊢ ( ¬  ∃ 𝑓  ∈  States ( 𝑓 ‘ 𝐴 )  =  1  ↔  𝐴  =  0ℋ ) | 
						
							| 18 | 17 | con1bii | ⊢ ( ¬  𝐴  =  0ℋ  ↔  ∃ 𝑓  ∈  States ( 𝑓 ‘ 𝐴 )  =  1 ) |