| Step | Hyp | Ref | Expression | 
						
							| 1 |  | elfzole1 |  | 
						
							| 2 |  | elfzoelz |  | 
						
							| 3 | 2 | zred |  | 
						
							| 4 | 3 | adantr |  | 
						
							| 5 |  | nn0addge1 |  | 
						
							| 6 | 4 5 | sylan |  | 
						
							| 7 |  | elfzoel1 |  | 
						
							| 8 | 7 | zred |  | 
						
							| 9 | 8 | adantr |  | 
						
							| 10 | 3 | adantr |  | 
						
							| 11 |  | nn0re |  | 
						
							| 12 | 11 | adantl |  | 
						
							| 13 | 10 12 | readdcld |  | 
						
							| 14 |  | letr |  | 
						
							| 15 | 9 10 13 14 | syl3anc |  | 
						
							| 16 | 15 | exp4b |  | 
						
							| 17 | 16 | com23 |  | 
						
							| 18 | 17 | imp31 |  | 
						
							| 19 | 6 18 | mpd |  | 
						
							| 20 | 19 | exp31 |  | 
						
							| 21 | 1 20 | mpd |  | 
						
							| 22 | 21 | imp |  | 
						
							| 23 |  | elfzoel2 |  | 
						
							| 24 | 23 | zred |  | 
						
							| 25 | 24 | adantr |  | 
						
							| 26 |  | elfzolt2 |  | 
						
							| 27 | 26 | adantr |  | 
						
							| 28 | 10 25 12 27 | ltadd1dd |  | 
						
							| 29 | 2 | adantr |  | 
						
							| 30 |  | nn0z |  | 
						
							| 31 | 30 | adantl |  | 
						
							| 32 | 29 31 | zaddcld |  | 
						
							| 33 | 7 | adantr |  | 
						
							| 34 | 23 | adantr |  | 
						
							| 35 | 34 31 | zaddcld |  | 
						
							| 36 |  | elfzo |  | 
						
							| 37 | 32 33 35 36 | syl3anc |  | 
						
							| 38 | 22 28 37 | mpbir2and |  |