| Step | Hyp | Ref | Expression | 
						
							| 1 |  | gsumws4.0 |  | 
						
							| 2 |  | gsumws4.1 |  | 
						
							| 3 |  | s1s3 |  | 
						
							| 4 | 3 | a1i |  | 
						
							| 5 | 4 | oveq2d |  | 
						
							| 6 |  | simpl |  | 
						
							| 7 |  | simprl |  | 
						
							| 8 | 7 | s1cld |  | 
						
							| 9 |  | simprrl |  | 
						
							| 10 |  | simprrl |  | 
						
							| 11 | 10 | adantl |  | 
						
							| 12 |  | simprrr |  | 
						
							| 13 | 12 | adantl |  | 
						
							| 14 | 9 11 13 | s3cld |  | 
						
							| 15 | 1 2 | gsumccat |  | 
						
							| 16 | 6 8 14 15 | syl3anc |  | 
						
							| 17 | 1 | gsumws1 |  | 
						
							| 18 | 17 | ad2antrl |  | 
						
							| 19 | 1 2 | gsumws3 |  | 
						
							| 20 | 19 | adantrl |  | 
						
							| 21 | 18 20 | oveq12d |  | 
						
							| 22 | 5 16 21 | 3eqtrd |  |