| Step | Hyp | Ref | Expression | 
						
							| 1 |  | simpll | ⊢ ( ( ( 𝑎  ∈  ℕ  ∧  𝑑  ∈  ℕ )  ∧  𝑚  ∈  ( 0 ... ( 𝐾  −  1 ) ) )  →  𝑎  ∈  ℕ ) | 
						
							| 2 |  | elfznn0 | ⊢ ( 𝑚  ∈  ( 0 ... ( 𝐾  −  1 ) )  →  𝑚  ∈  ℕ0 ) | 
						
							| 3 | 2 | adantl | ⊢ ( ( ( 𝑎  ∈  ℕ  ∧  𝑑  ∈  ℕ )  ∧  𝑚  ∈  ( 0 ... ( 𝐾  −  1 ) ) )  →  𝑚  ∈  ℕ0 ) | 
						
							| 4 |  | nnnn0 | ⊢ ( 𝑑  ∈  ℕ  →  𝑑  ∈  ℕ0 ) | 
						
							| 5 | 4 | ad2antlr | ⊢ ( ( ( 𝑎  ∈  ℕ  ∧  𝑑  ∈  ℕ )  ∧  𝑚  ∈  ( 0 ... ( 𝐾  −  1 ) ) )  →  𝑑  ∈  ℕ0 ) | 
						
							| 6 | 3 5 | nn0mulcld | ⊢ ( ( ( 𝑎  ∈  ℕ  ∧  𝑑  ∈  ℕ )  ∧  𝑚  ∈  ( 0 ... ( 𝐾  −  1 ) ) )  →  ( 𝑚  ·  𝑑 )  ∈  ℕ0 ) | 
						
							| 7 |  | nnnn0addcl | ⊢ ( ( 𝑎  ∈  ℕ  ∧  ( 𝑚  ·  𝑑 )  ∈  ℕ0 )  →  ( 𝑎  +  ( 𝑚  ·  𝑑 ) )  ∈  ℕ ) | 
						
							| 8 | 1 6 7 | syl2anc | ⊢ ( ( ( 𝑎  ∈  ℕ  ∧  𝑑  ∈  ℕ )  ∧  𝑚  ∈  ( 0 ... ( 𝐾  −  1 ) ) )  →  ( 𝑎  +  ( 𝑚  ·  𝑑 ) )  ∈  ℕ ) | 
						
							| 9 | 8 | fmpttd | ⊢ ( ( 𝑎  ∈  ℕ  ∧  𝑑  ∈  ℕ )  →  ( 𝑚  ∈  ( 0 ... ( 𝐾  −  1 ) )  ↦  ( 𝑎  +  ( 𝑚  ·  𝑑 ) ) ) : ( 0 ... ( 𝐾  −  1 ) ) ⟶ ℕ ) | 
						
							| 10 | 9 | frnd | ⊢ ( ( 𝑎  ∈  ℕ  ∧  𝑑  ∈  ℕ )  →  ran  ( 𝑚  ∈  ( 0 ... ( 𝐾  −  1 ) )  ↦  ( 𝑎  +  ( 𝑚  ·  𝑑 ) ) )  ⊆  ℕ ) | 
						
							| 11 |  | nnex | ⊢ ℕ  ∈  V | 
						
							| 12 | 11 | elpw2 | ⊢ ( ran  ( 𝑚  ∈  ( 0 ... ( 𝐾  −  1 ) )  ↦  ( 𝑎  +  ( 𝑚  ·  𝑑 ) ) )  ∈  𝒫  ℕ  ↔  ran  ( 𝑚  ∈  ( 0 ... ( 𝐾  −  1 ) )  ↦  ( 𝑎  +  ( 𝑚  ·  𝑑 ) ) )  ⊆  ℕ ) | 
						
							| 13 | 10 12 | sylibr | ⊢ ( ( 𝑎  ∈  ℕ  ∧  𝑑  ∈  ℕ )  →  ran  ( 𝑚  ∈  ( 0 ... ( 𝐾  −  1 ) )  ↦  ( 𝑎  +  ( 𝑚  ·  𝑑 ) ) )  ∈  𝒫  ℕ ) | 
						
							| 14 | 13 | rgen2 | ⊢ ∀ 𝑎  ∈  ℕ ∀ 𝑑  ∈  ℕ ran  ( 𝑚  ∈  ( 0 ... ( 𝐾  −  1 ) )  ↦  ( 𝑎  +  ( 𝑚  ·  𝑑 ) ) )  ∈  𝒫  ℕ | 
						
							| 15 |  | eqid | ⊢ ( 𝑎  ∈  ℕ ,  𝑑  ∈  ℕ  ↦  ran  ( 𝑚  ∈  ( 0 ... ( 𝐾  −  1 ) )  ↦  ( 𝑎  +  ( 𝑚  ·  𝑑 ) ) ) )  =  ( 𝑎  ∈  ℕ ,  𝑑  ∈  ℕ  ↦  ran  ( 𝑚  ∈  ( 0 ... ( 𝐾  −  1 ) )  ↦  ( 𝑎  +  ( 𝑚  ·  𝑑 ) ) ) ) | 
						
							| 16 | 15 | fmpo | ⊢ ( ∀ 𝑎  ∈  ℕ ∀ 𝑑  ∈  ℕ ran  ( 𝑚  ∈  ( 0 ... ( 𝐾  −  1 ) )  ↦  ( 𝑎  +  ( 𝑚  ·  𝑑 ) ) )  ∈  𝒫  ℕ  ↔  ( 𝑎  ∈  ℕ ,  𝑑  ∈  ℕ  ↦  ran  ( 𝑚  ∈  ( 0 ... ( 𝐾  −  1 ) )  ↦  ( 𝑎  +  ( 𝑚  ·  𝑑 ) ) ) ) : ( ℕ  ×  ℕ ) ⟶ 𝒫  ℕ ) | 
						
							| 17 | 14 16 | mpbi | ⊢ ( 𝑎  ∈  ℕ ,  𝑑  ∈  ℕ  ↦  ran  ( 𝑚  ∈  ( 0 ... ( 𝐾  −  1 ) )  ↦  ( 𝑎  +  ( 𝑚  ·  𝑑 ) ) ) ) : ( ℕ  ×  ℕ ) ⟶ 𝒫  ℕ | 
						
							| 18 |  | vdwapfval | ⊢ ( 𝐾  ∈  ℕ0  →  ( AP ‘ 𝐾 )  =  ( 𝑎  ∈  ℕ ,  𝑑  ∈  ℕ  ↦  ran  ( 𝑚  ∈  ( 0 ... ( 𝐾  −  1 ) )  ↦  ( 𝑎  +  ( 𝑚  ·  𝑑 ) ) ) ) ) | 
						
							| 19 | 18 | feq1d | ⊢ ( 𝐾  ∈  ℕ0  →  ( ( AP ‘ 𝐾 ) : ( ℕ  ×  ℕ ) ⟶ 𝒫  ℕ  ↔  ( 𝑎  ∈  ℕ ,  𝑑  ∈  ℕ  ↦  ran  ( 𝑚  ∈  ( 0 ... ( 𝐾  −  1 ) )  ↦  ( 𝑎  +  ( 𝑚  ·  𝑑 ) ) ) ) : ( ℕ  ×  ℕ ) ⟶ 𝒫  ℕ ) ) | 
						
							| 20 | 17 19 | mpbiri | ⊢ ( 𝐾  ∈  ℕ0  →  ( AP ‘ 𝐾 ) : ( ℕ  ×  ℕ ) ⟶ 𝒫  ℕ ) |