| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 3factsumint3.1 |  | 
						
							| 2 |  | 3factsumint3.2 |  | 
						
							| 3 |  | 3factsumint3.3 |  | 
						
							| 4 |  | 3factsumint3.4 |  | 
						
							| 5 |  | 3factsumint3.5 |  | 
						
							| 6 |  | 3factsumint3.6 |  | 
						
							| 7 |  | 3factsumint3.7 |  | 
						
							| 8 |  | 3factsumint3.8 |  | 
						
							| 9 | 4 | adantlr |  | 
						
							| 10 |  | ancom |  | 
						
							| 11 | 10 | anbi2i |  | 
						
							| 12 |  | anass |  | 
						
							| 13 | 12 | bicomi |  | 
						
							| 14 | 11 13 | bitri |  | 
						
							| 15 | 14 | imbi1i |  | 
						
							| 16 | 7 15 | mpbi |  | 
						
							| 17 | 9 16 | mulcld |  | 
						
							| 18 | 2 | adantr |  | 
						
							| 19 | 3 | adantr |  | 
						
							| 20 | 5 | adantr |  | 
						
							| 21 | 20 8 | mulcncf |  | 
						
							| 22 | 1 | oveq1i |  | 
						
							| 23 | 21 22 | eleqtrdi |  | 
						
							| 24 |  | cnicciblnc |  | 
						
							| 25 | 18 19 23 24 | syl3anc |  | 
						
							| 26 | 6 17 25 | itgmulc2 |  | 
						
							| 27 | 26 | eqcomd |  | 
						
							| 28 | 27 | sumeq2dv |  |