| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mndvcl.b | ⊢ 𝐵  =  ( Base ‘ 𝑀 ) | 
						
							| 2 |  | mndvcl.p | ⊢  +   =  ( +g ‘ 𝑀 ) | 
						
							| 3 |  | mndvlid.z | ⊢  0   =  ( 0g ‘ 𝑀 ) | 
						
							| 4 |  | elmapex | ⊢ ( 𝑋  ∈  ( 𝐵  ↑m  𝐼 )  →  ( 𝐵  ∈  V  ∧  𝐼  ∈  V ) ) | 
						
							| 5 | 4 | simprd | ⊢ ( 𝑋  ∈  ( 𝐵  ↑m  𝐼 )  →  𝐼  ∈  V ) | 
						
							| 6 | 5 | adantl | ⊢ ( ( 𝑀  ∈  Mnd  ∧  𝑋  ∈  ( 𝐵  ↑m  𝐼 ) )  →  𝐼  ∈  V ) | 
						
							| 7 |  | elmapi | ⊢ ( 𝑋  ∈  ( 𝐵  ↑m  𝐼 )  →  𝑋 : 𝐼 ⟶ 𝐵 ) | 
						
							| 8 | 7 | adantl | ⊢ ( ( 𝑀  ∈  Mnd  ∧  𝑋  ∈  ( 𝐵  ↑m  𝐼 ) )  →  𝑋 : 𝐼 ⟶ 𝐵 ) | 
						
							| 9 | 1 3 | mndidcl | ⊢ ( 𝑀  ∈  Mnd  →   0   ∈  𝐵 ) | 
						
							| 10 | 9 | adantr | ⊢ ( ( 𝑀  ∈  Mnd  ∧  𝑋  ∈  ( 𝐵  ↑m  𝐼 ) )  →   0   ∈  𝐵 ) | 
						
							| 11 | 1 2 3 | mndrid | ⊢ ( ( 𝑀  ∈  Mnd  ∧  𝑥  ∈  𝐵 )  →  ( 𝑥  +   0  )  =  𝑥 ) | 
						
							| 12 | 11 | adantlr | ⊢ ( ( ( 𝑀  ∈  Mnd  ∧  𝑋  ∈  ( 𝐵  ↑m  𝐼 ) )  ∧  𝑥  ∈  𝐵 )  →  ( 𝑥  +   0  )  =  𝑥 ) | 
						
							| 13 | 6 8 10 12 | caofid0r | ⊢ ( ( 𝑀  ∈  Mnd  ∧  𝑋  ∈  ( 𝐵  ↑m  𝐼 ) )  →  ( 𝑋  ∘f   +  ( 𝐼  ×  {  0  } ) )  =  𝑋 ) |