| Step | Hyp | Ref | Expression | 
						
							| 1 |  | gsumspl.b |  | 
						
							| 2 |  | gsumspl.m |  | 
						
							| 3 |  | gsumspl.s |  | 
						
							| 4 |  | gsumspl.f |  | 
						
							| 5 |  | gsumspl.t |  | 
						
							| 6 |  | gsumspl.x |  | 
						
							| 7 |  | gsumspl.y |  | 
						
							| 8 |  | gsumspl.eq |  | 
						
							| 9 | 8 | oveq2d |  | 
						
							| 10 | 9 | oveq1d |  | 
						
							| 11 |  | splval |  | 
						
							| 12 | 3 4 5 6 11 | syl13anc |  | 
						
							| 13 | 12 | oveq2d |  | 
						
							| 14 |  | pfxcl |  | 
						
							| 15 | 3 14 | syl |  | 
						
							| 16 |  | ccatcl |  | 
						
							| 17 | 15 6 16 | syl2anc |  | 
						
							| 18 |  | swrdcl |  | 
						
							| 19 | 3 18 | syl |  | 
						
							| 20 |  | eqid |  | 
						
							| 21 | 1 20 | gsumccat |  | 
						
							| 22 | 2 17 19 21 | syl3anc |  | 
						
							| 23 | 1 20 | gsumccat |  | 
						
							| 24 | 2 15 6 23 | syl3anc |  | 
						
							| 25 | 24 | oveq1d |  | 
						
							| 26 | 13 22 25 | 3eqtrd |  | 
						
							| 27 |  | splval |  | 
						
							| 28 | 3 4 5 7 27 | syl13anc |  | 
						
							| 29 | 28 | oveq2d |  | 
						
							| 30 |  | ccatcl |  | 
						
							| 31 | 15 7 30 | syl2anc |  | 
						
							| 32 | 1 20 | gsumccat |  | 
						
							| 33 | 2 31 19 32 | syl3anc |  | 
						
							| 34 | 1 20 | gsumccat |  | 
						
							| 35 | 2 15 7 34 | syl3anc |  | 
						
							| 36 | 35 | oveq1d |  | 
						
							| 37 | 29 33 36 | 3eqtrd |  | 
						
							| 38 | 10 26 37 | 3eqtr4d |  |