| Step | Hyp | Ref | Expression | 
						
							| 1 |  | df-nan | ⊢ ( ( 𝜑  ⊼  𝜓 )  ↔  ¬  ( 𝜑  ∧  𝜓 ) ) | 
						
							| 2 |  | xor2 | ⊢ ( ( 𝜑  ⊻  𝜓 )  ↔  ( ( 𝜑  ∨  𝜓 )  ∧  ¬  ( 𝜑  ∧  𝜓 ) ) ) | 
						
							| 3 | 2 | rbaibr | ⊢ ( ¬  ( 𝜑  ∧  𝜓 )  →  ( ( 𝜑  ∨  𝜓 )  ↔  ( 𝜑  ⊻  𝜓 ) ) ) | 
						
							| 4 | 2 | bibi2i | ⊢ ( ( ( 𝜑  ∨  𝜓 )  ↔  ( 𝜑  ⊻  𝜓 ) )  ↔  ( ( 𝜑  ∨  𝜓 )  ↔  ( ( 𝜑  ∨  𝜓 )  ∧  ¬  ( 𝜑  ∧  𝜓 ) ) ) ) | 
						
							| 5 |  | pm4.71 | ⊢ ( ( ( 𝜑  ∨  𝜓 )  →  ¬  ( 𝜑  ∧  𝜓 ) )  ↔  ( ( 𝜑  ∨  𝜓 )  ↔  ( ( 𝜑  ∨  𝜓 )  ∧  ¬  ( 𝜑  ∧  𝜓 ) ) ) ) | 
						
							| 6 |  | simpl | ⊢ ( ( 𝜑  ∧  𝜓 )  →  𝜑 ) | 
						
							| 7 | 6 | orcd | ⊢ ( ( 𝜑  ∧  𝜓 )  →  ( 𝜑  ∨  𝜓 ) ) | 
						
							| 8 | 7 | con3i | ⊢ ( ¬  ( 𝜑  ∨  𝜓 )  →  ¬  ( 𝜑  ∧  𝜓 ) ) | 
						
							| 9 |  | id | ⊢ ( ¬  ( 𝜑  ∧  𝜓 )  →  ¬  ( 𝜑  ∧  𝜓 ) ) | 
						
							| 10 | 8 9 | ja | ⊢ ( ( ( 𝜑  ∨  𝜓 )  →  ¬  ( 𝜑  ∧  𝜓 ) )  →  ¬  ( 𝜑  ∧  𝜓 ) ) | 
						
							| 11 | 5 10 | sylbir | ⊢ ( ( ( 𝜑  ∨  𝜓 )  ↔  ( ( 𝜑  ∨  𝜓 )  ∧  ¬  ( 𝜑  ∧  𝜓 ) ) )  →  ¬  ( 𝜑  ∧  𝜓 ) ) | 
						
							| 12 | 4 11 | sylbi | ⊢ ( ( ( 𝜑  ∨  𝜓 )  ↔  ( 𝜑  ⊻  𝜓 ) )  →  ¬  ( 𝜑  ∧  𝜓 ) ) | 
						
							| 13 | 3 12 | impbii | ⊢ ( ¬  ( 𝜑  ∧  𝜓 )  ↔  ( ( 𝜑  ∨  𝜓 )  ↔  ( 𝜑  ⊻  𝜓 ) ) ) | 
						
							| 14 | 1 13 | bitri | ⊢ ( ( 𝜑  ⊼  𝜓 )  ↔  ( ( 𝜑  ∨  𝜓 )  ↔  ( 𝜑  ⊻  𝜓 ) ) ) |