| Step | Hyp | Ref | Expression | 
						
							| 1 |  | nic-dfim | ⊢ ( ( ( 𝜑  ⊼  ( 𝜓  ⊼  𝜓 ) )  ⊼  ( 𝜑  →  𝜓 ) )  ⊼  ( ( ( 𝜑  ⊼  ( 𝜓  ⊼  𝜓 ) )  ⊼  ( 𝜑  ⊼  ( 𝜓  ⊼  𝜓 ) ) )  ⊼  ( ( 𝜑  →  𝜓 )  ⊼  ( 𝜑  →  𝜓 ) ) ) ) | 
						
							| 2 | 1 | nic-bi2 | ⊢ ( ( 𝜑  →  𝜓 )  ⊼  ( ( 𝜑  ⊼  ( 𝜓  ⊼  𝜓 ) )  ⊼  ( 𝜑  ⊼  ( 𝜓  ⊼  𝜓 ) ) ) ) | 
						
							| 3 |  | nic-ax | ⊢ ( ( 𝜑  ⊼  ( 𝜓  ⊼  𝜓 ) )  ⊼  ( ( 𝜏  ⊼  ( 𝜏  ⊼  𝜏 ) )  ⊼  ( ( ( 𝜒  ⊼  𝜒 )  ⊼  𝜓 )  ⊼  ( ( 𝜑  ⊼  ( 𝜒  ⊼  𝜒 ) )  ⊼  ( 𝜑  ⊼  ( 𝜒  ⊼  𝜒 ) ) ) ) ) ) | 
						
							| 4 | 3 | nic-isw2 | ⊢ ( ( 𝜑  ⊼  ( 𝜓  ⊼  𝜓 ) )  ⊼  ( ( ( ( 𝜒  ⊼  𝜒 )  ⊼  𝜓 )  ⊼  ( ( 𝜑  ⊼  ( 𝜒  ⊼  𝜒 ) )  ⊼  ( 𝜑  ⊼  ( 𝜒  ⊼  𝜒 ) ) ) )  ⊼  ( 𝜏  ⊼  ( 𝜏  ⊼  𝜏 ) ) ) ) | 
						
							| 5 | 4 | nic-idel | ⊢ ( ( 𝜑  ⊼  ( 𝜓  ⊼  𝜓 ) )  ⊼  ( ( ( ( 𝜒  ⊼  𝜒 )  ⊼  𝜓 )  ⊼  ( ( 𝜑  ⊼  ( 𝜒  ⊼  𝜒 ) )  ⊼  ( 𝜑  ⊼  ( 𝜒  ⊼  𝜒 ) ) ) )  ⊼  ( ( ( 𝜒  ⊼  𝜒 )  ⊼  𝜓 )  ⊼  ( ( 𝜑  ⊼  ( 𝜒  ⊼  𝜒 ) )  ⊼  ( 𝜑  ⊼  ( 𝜒  ⊼  𝜒 ) ) ) ) ) ) | 
						
							| 6 |  | nic-dfim | ⊢ ( ( ( 𝜑  ⊼  ( 𝜒  ⊼  𝜒 ) )  ⊼  ( 𝜑  →  𝜒 ) )  ⊼  ( ( ( 𝜑  ⊼  ( 𝜒  ⊼  𝜒 ) )  ⊼  ( 𝜑  ⊼  ( 𝜒  ⊼  𝜒 ) ) )  ⊼  ( ( 𝜑  →  𝜒 )  ⊼  ( 𝜑  →  𝜒 ) ) ) ) | 
						
							| 7 | 6 | nic-bi1 | ⊢ ( ( 𝜑  ⊼  ( 𝜒  ⊼  𝜒 ) )  ⊼  ( ( 𝜑  →  𝜒 )  ⊼  ( 𝜑  →  𝜒 ) ) ) | 
						
							| 8 | 7 | nic-idbl | ⊢ ( ( ( 𝜑  →  𝜒 )  ⊼  ( 𝜑  →  𝜒 ) )  ⊼  ( ( ( 𝜑  ⊼  ( 𝜒  ⊼  𝜒 ) )  ⊼  ( 𝜑  ⊼  ( 𝜒  ⊼  𝜒 ) ) )  ⊼  ( ( 𝜑  ⊼  ( 𝜒  ⊼  𝜒 ) )  ⊼  ( 𝜑  ⊼  ( 𝜒  ⊼  𝜒 ) ) ) ) ) | 
						
							| 9 | 8 | nic-imp | ⊢ ( ( ( ( 𝜒  ⊼  𝜒 )  ⊼  𝜓 )  ⊼  ( ( 𝜑  ⊼  ( 𝜒  ⊼  𝜒 ) )  ⊼  ( 𝜑  ⊼  ( 𝜒  ⊼  𝜒 ) ) ) )  ⊼  ( ( ( ( 𝜑  →  𝜒 )  ⊼  ( 𝜑  →  𝜒 ) )  ⊼  ( ( 𝜒  ⊼  𝜒 )  ⊼  𝜓 ) )  ⊼  ( ( ( 𝜑  →  𝜒 )  ⊼  ( 𝜑  →  𝜒 ) )  ⊼  ( ( 𝜒  ⊼  𝜒 )  ⊼  𝜓 ) ) ) ) | 
						
							| 10 |  | nic-dfim | ⊢ ( ( ( 𝜓  ⊼  ( 𝜒  ⊼  𝜒 ) )  ⊼  ( 𝜓  →  𝜒 ) )  ⊼  ( ( ( 𝜓  ⊼  ( 𝜒  ⊼  𝜒 ) )  ⊼  ( 𝜓  ⊼  ( 𝜒  ⊼  𝜒 ) ) )  ⊼  ( ( 𝜓  →  𝜒 )  ⊼  ( 𝜓  →  𝜒 ) ) ) ) | 
						
							| 11 | 10 | nic-bi2 | ⊢ ( ( 𝜓  →  𝜒 )  ⊼  ( ( 𝜓  ⊼  ( 𝜒  ⊼  𝜒 ) )  ⊼  ( 𝜓  ⊼  ( 𝜒  ⊼  𝜒 ) ) ) ) | 
						
							| 12 |  | nic-swap | ⊢ ( ( 𝜓  ⊼  ( 𝜒  ⊼  𝜒 ) )  ⊼  ( ( ( 𝜒  ⊼  𝜒 )  ⊼  𝜓 )  ⊼  ( ( 𝜒  ⊼  𝜒 )  ⊼  𝜓 ) ) ) | 
						
							| 13 | 11 12 | nic-ich | ⊢ ( ( 𝜓  →  𝜒 )  ⊼  ( ( ( 𝜒  ⊼  𝜒 )  ⊼  𝜓 )  ⊼  ( ( 𝜒  ⊼  𝜒 )  ⊼  𝜓 ) ) ) | 
						
							| 14 | 13 | nic-imp | ⊢ ( ( ( ( 𝜑  →  𝜒 )  ⊼  ( 𝜑  →  𝜒 ) )  ⊼  ( ( 𝜒  ⊼  𝜒 )  ⊼  𝜓 ) )  ⊼  ( ( ( 𝜓  →  𝜒 )  ⊼  ( ( 𝜑  →  𝜒 )  ⊼  ( 𝜑  →  𝜒 ) ) )  ⊼  ( ( 𝜓  →  𝜒 )  ⊼  ( ( 𝜑  →  𝜒 )  ⊼  ( 𝜑  →  𝜒 ) ) ) ) ) | 
						
							| 15 | 9 14 | nic-ich | ⊢ ( ( ( ( 𝜒  ⊼  𝜒 )  ⊼  𝜓 )  ⊼  ( ( 𝜑  ⊼  ( 𝜒  ⊼  𝜒 ) )  ⊼  ( 𝜑  ⊼  ( 𝜒  ⊼  𝜒 ) ) ) )  ⊼  ( ( ( 𝜓  →  𝜒 )  ⊼  ( ( 𝜑  →  𝜒 )  ⊼  ( 𝜑  →  𝜒 ) ) )  ⊼  ( ( 𝜓  →  𝜒 )  ⊼  ( ( 𝜑  →  𝜒 )  ⊼  ( 𝜑  →  𝜒 ) ) ) ) ) | 
						
							| 16 | 5 15 | nic-ich | ⊢ ( ( 𝜑  ⊼  ( 𝜓  ⊼  𝜓 ) )  ⊼  ( ( ( 𝜓  →  𝜒 )  ⊼  ( ( 𝜑  →  𝜒 )  ⊼  ( 𝜑  →  𝜒 ) ) )  ⊼  ( ( 𝜓  →  𝜒 )  ⊼  ( ( 𝜑  →  𝜒 )  ⊼  ( 𝜑  →  𝜒 ) ) ) ) ) | 
						
							| 17 |  | nic-dfim | ⊢ ( ( ( ( 𝜓  →  𝜒 )  ⊼  ( ( 𝜑  →  𝜒 )  ⊼  ( 𝜑  →  𝜒 ) ) )  ⊼  ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) ) )  ⊼  ( ( ( ( 𝜓  →  𝜒 )  ⊼  ( ( 𝜑  →  𝜒 )  ⊼  ( 𝜑  →  𝜒 ) ) )  ⊼  ( ( 𝜓  →  𝜒 )  ⊼  ( ( 𝜑  →  𝜒 )  ⊼  ( 𝜑  →  𝜒 ) ) ) )  ⊼  ( ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) )  ⊼  ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) ) ) ) ) | 
						
							| 18 | 17 | nic-bi1 | ⊢ ( ( ( 𝜓  →  𝜒 )  ⊼  ( ( 𝜑  →  𝜒 )  ⊼  ( 𝜑  →  𝜒 ) ) )  ⊼  ( ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) )  ⊼  ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) ) ) ) | 
						
							| 19 | 16 18 | nic-ich | ⊢ ( ( 𝜑  ⊼  ( 𝜓  ⊼  𝜓 ) )  ⊼  ( ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) )  ⊼  ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) ) ) ) | 
						
							| 20 | 2 19 | nic-ich | ⊢ ( ( 𝜑  →  𝜓 )  ⊼  ( ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) )  ⊼  ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) ) ) ) | 
						
							| 21 |  | nic-dfim | ⊢ ( ( ( ( 𝜑  →  𝜓 )  ⊼  ( ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) )  ⊼  ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) ) ) )  ⊼  ( ( 𝜑  →  𝜓 )  →  ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) ) ) )  ⊼  ( ( ( ( 𝜑  →  𝜓 )  ⊼  ( ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) )  ⊼  ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) ) ) )  ⊼  ( ( 𝜑  →  𝜓 )  ⊼  ( ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) )  ⊼  ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) ) ) ) )  ⊼  ( ( ( 𝜑  →  𝜓 )  →  ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) ) )  ⊼  ( ( 𝜑  →  𝜓 )  →  ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) ) ) ) ) ) | 
						
							| 22 | 21 | nic-bi1 | ⊢ ( ( ( 𝜑  →  𝜓 )  ⊼  ( ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) )  ⊼  ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) ) ) )  ⊼  ( ( ( 𝜑  →  𝜓 )  →  ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) ) )  ⊼  ( ( 𝜑  →  𝜓 )  →  ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) ) ) ) ) | 
						
							| 23 | 20 22 | nic-mp | ⊢ ( ( 𝜑  →  𝜓 )  →  ( ( 𝜓  →  𝜒 )  →  ( 𝜑  →  𝜒 ) ) ) |