| Step | Hyp | Ref | Expression | 
						
							| 1 |  | gsummptfidmadd.b | ⊢ 𝐵  =  ( Base ‘ 𝐺 ) | 
						
							| 2 |  | gsummptfidmadd.p | ⊢  +   =  ( +g ‘ 𝐺 ) | 
						
							| 3 |  | gsummptfidmadd.g | ⊢ ( 𝜑  →  𝐺  ∈  CMnd ) | 
						
							| 4 |  | gsummptfidmadd.a | ⊢ ( 𝜑  →  𝐴  ∈  Fin ) | 
						
							| 5 |  | gsummptfidmadd.c | ⊢ ( ( 𝜑  ∧  𝑥  ∈  𝐴 )  →  𝐶  ∈  𝐵 ) | 
						
							| 6 |  | gsummptfidmadd.d | ⊢ ( ( 𝜑  ∧  𝑥  ∈  𝐴 )  →  𝐷  ∈  𝐵 ) | 
						
							| 7 |  | gsummptfidmadd.f | ⊢ 𝐹  =  ( 𝑥  ∈  𝐴  ↦  𝐶 ) | 
						
							| 8 |  | gsummptfidmadd.h | ⊢ 𝐻  =  ( 𝑥  ∈  𝐴  ↦  𝐷 ) | 
						
							| 9 | 7 | a1i | ⊢ ( 𝜑  →  𝐹  =  ( 𝑥  ∈  𝐴  ↦  𝐶 ) ) | 
						
							| 10 | 8 | a1i | ⊢ ( 𝜑  →  𝐻  =  ( 𝑥  ∈  𝐴  ↦  𝐷 ) ) | 
						
							| 11 | 4 5 6 9 10 | offval2 | ⊢ ( 𝜑  →  ( 𝐹  ∘f   +  𝐻 )  =  ( 𝑥  ∈  𝐴  ↦  ( 𝐶  +  𝐷 ) ) ) | 
						
							| 12 | 11 | oveq2d | ⊢ ( 𝜑  →  ( 𝐺  Σg  ( 𝐹  ∘f   +  𝐻 ) )  =  ( 𝐺  Σg  ( 𝑥  ∈  𝐴  ↦  ( 𝐶  +  𝐷 ) ) ) ) | 
						
							| 13 | 1 2 3 4 5 6 7 8 | gsummptfidmadd | ⊢ ( 𝜑  →  ( 𝐺  Σg  ( 𝑥  ∈  𝐴  ↦  ( 𝐶  +  𝐷 ) ) )  =  ( ( 𝐺  Σg  𝐹 )  +  ( 𝐺  Σg  𝐻 ) ) ) | 
						
							| 14 | 12 13 | eqtrd | ⊢ ( 𝜑  →  ( 𝐺  Σg  ( 𝐹  ∘f   +  𝐻 ) )  =  ( ( 𝐺  Σg  𝐹 )  +  ( 𝐺  Σg  𝐻 ) ) ) |