| Step | Hyp | Ref | Expression | 
						
							| 1 |  | frn |  | 
						
							| 2 | 1 | 3ad2ant3 |  | 
						
							| 3 |  | nn0ssz |  | 
						
							| 4 | 2 3 | sstrdi |  | 
						
							| 5 |  | nn0ssre |  | 
						
							| 6 | 2 5 | sstrdi |  | 
						
							| 7 |  | simp1 |  | 
						
							| 8 |  | ffn |  | 
						
							| 9 | 8 | 3ad2ant3 |  | 
						
							| 10 |  | dffn4 |  | 
						
							| 11 | 9 10 | sylib |  | 
						
							| 12 |  | fofi |  | 
						
							| 13 | 7 11 12 | syl2anc |  | 
						
							| 14 |  | fdm |  | 
						
							| 15 | 14 | 3ad2ant3 |  | 
						
							| 16 |  | simp2 |  | 
						
							| 17 | 15 16 | eqnetrd |  | 
						
							| 18 |  | dm0rn0 |  | 
						
							| 19 | 18 | necon3bii |  | 
						
							| 20 | 17 19 | sylib |  | 
						
							| 21 |  | fimaxre |  | 
						
							| 22 | 6 13 20 21 | syl3anc |  | 
						
							| 23 |  | ssrexv |  | 
						
							| 24 | 4 22 23 | sylc |  | 
						
							| 25 |  | 0ram |  | 
						
							| 26 | 24 25 | mpdan |  |