| Step | Hyp | Ref | Expression | 
						
							| 1 |  | esumcl.1 |  | 
						
							| 2 |  | xrge0base |  | 
						
							| 3 |  | xrge0cmn |  | 
						
							| 4 | 3 | a1i |  | 
						
							| 5 |  | xrge0tps |  | 
						
							| 6 | 5 | a1i |  | 
						
							| 7 |  | simpl |  | 
						
							| 8 | 1 | nfel1 |  | 
						
							| 9 |  | nfra1 |  | 
						
							| 10 | 8 9 | nfan |  | 
						
							| 11 |  | nfcv |  | 
						
							| 12 |  | simpr |  | 
						
							| 13 | 12 | r19.21bi |  | 
						
							| 14 |  | eqid |  | 
						
							| 15 | 10 1 11 13 14 | fmptdF |  | 
						
							| 16 | 2 4 6 7 15 | tsmscl |  | 
						
							| 17 |  | df-esum |  | 
						
							| 18 |  | eqid |  | 
						
							| 19 | 18 7 15 | xrge0tsmsbi |  | 
						
							| 20 | 17 19 | mpbiri |  | 
						
							| 21 | 16 20 | sseldd |  |