| Step | Hyp | Ref | Expression | 
						
							| 1 |  | axlowdimlem10.1 | ⊢ 𝑄  =  ( { 〈 ( 𝐼  +  1 ) ,  1 〉 }  ∪  ( ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } )  ×  { 0 } ) ) | 
						
							| 2 |  | ovex | ⊢ ( 𝐼  +  1 )  ∈  V | 
						
							| 3 |  | 1ex | ⊢ 1  ∈  V | 
						
							| 4 | 2 3 | f1osn | ⊢ { 〈 ( 𝐼  +  1 ) ,  1 〉 } : { ( 𝐼  +  1 ) } –1-1-onto→ { 1 } | 
						
							| 5 |  | f1of | ⊢ ( { 〈 ( 𝐼  +  1 ) ,  1 〉 } : { ( 𝐼  +  1 ) } –1-1-onto→ { 1 }  →  { 〈 ( 𝐼  +  1 ) ,  1 〉 } : { ( 𝐼  +  1 ) } ⟶ { 1 } ) | 
						
							| 6 | 4 5 | ax-mp | ⊢ { 〈 ( 𝐼  +  1 ) ,  1 〉 } : { ( 𝐼  +  1 ) } ⟶ { 1 } | 
						
							| 7 |  | c0ex | ⊢ 0  ∈  V | 
						
							| 8 | 7 | fconst | ⊢ ( ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } )  ×  { 0 } ) : ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) ⟶ { 0 } | 
						
							| 9 | 6 8 | pm3.2i | ⊢ ( { 〈 ( 𝐼  +  1 ) ,  1 〉 } : { ( 𝐼  +  1 ) } ⟶ { 1 }  ∧  ( ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } )  ×  { 0 } ) : ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) ⟶ { 0 } ) | 
						
							| 10 |  | disjdif | ⊢ ( { ( 𝐼  +  1 ) }  ∩  ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) )  =  ∅ | 
						
							| 11 |  | fun | ⊢ ( ( ( { 〈 ( 𝐼  +  1 ) ,  1 〉 } : { ( 𝐼  +  1 ) } ⟶ { 1 }  ∧  ( ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } )  ×  { 0 } ) : ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) ⟶ { 0 } )  ∧  ( { ( 𝐼  +  1 ) }  ∩  ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) )  =  ∅ )  →  ( { 〈 ( 𝐼  +  1 ) ,  1 〉 }  ∪  ( ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } )  ×  { 0 } ) ) : ( { ( 𝐼  +  1 ) }  ∪  ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) ) ⟶ ( { 1 }  ∪  { 0 } ) ) | 
						
							| 12 | 9 10 11 | mp2an | ⊢ ( { 〈 ( 𝐼  +  1 ) ,  1 〉 }  ∪  ( ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } )  ×  { 0 } ) ) : ( { ( 𝐼  +  1 ) }  ∪  ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) ) ⟶ ( { 1 }  ∪  { 0 } ) | 
						
							| 13 | 1 | feq1i | ⊢ ( 𝑄 : ( { ( 𝐼  +  1 ) }  ∪  ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) ) ⟶ ( { 1 }  ∪  { 0 } )  ↔  ( { 〈 ( 𝐼  +  1 ) ,  1 〉 }  ∪  ( ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } )  ×  { 0 } ) ) : ( { ( 𝐼  +  1 ) }  ∪  ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) ) ⟶ ( { 1 }  ∪  { 0 } ) ) | 
						
							| 14 | 12 13 | mpbir | ⊢ 𝑄 : ( { ( 𝐼  +  1 ) }  ∪  ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) ) ⟶ ( { 1 }  ∪  { 0 } ) | 
						
							| 15 |  | 1re | ⊢ 1  ∈  ℝ | 
						
							| 16 |  | snssi | ⊢ ( 1  ∈  ℝ  →  { 1 }  ⊆  ℝ ) | 
						
							| 17 | 15 16 | ax-mp | ⊢ { 1 }  ⊆  ℝ | 
						
							| 18 |  | 0re | ⊢ 0  ∈  ℝ | 
						
							| 19 |  | snssi | ⊢ ( 0  ∈  ℝ  →  { 0 }  ⊆  ℝ ) | 
						
							| 20 | 18 19 | ax-mp | ⊢ { 0 }  ⊆  ℝ | 
						
							| 21 | 17 20 | unssi | ⊢ ( { 1 }  ∪  { 0 } )  ⊆  ℝ | 
						
							| 22 |  | fss | ⊢ ( ( 𝑄 : ( { ( 𝐼  +  1 ) }  ∪  ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) ) ⟶ ( { 1 }  ∪  { 0 } )  ∧  ( { 1 }  ∪  { 0 } )  ⊆  ℝ )  →  𝑄 : ( { ( 𝐼  +  1 ) }  ∪  ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) ) ⟶ ℝ ) | 
						
							| 23 | 14 21 22 | mp2an | ⊢ 𝑄 : ( { ( 𝐼  +  1 ) }  ∪  ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) ) ⟶ ℝ | 
						
							| 24 |  | fznatpl1 | ⊢ ( ( 𝑁  ∈  ℕ  ∧  𝐼  ∈  ( 1 ... ( 𝑁  −  1 ) ) )  →  ( 𝐼  +  1 )  ∈  ( 1 ... 𝑁 ) ) | 
						
							| 25 | 24 | snssd | ⊢ ( ( 𝑁  ∈  ℕ  ∧  𝐼  ∈  ( 1 ... ( 𝑁  −  1 ) ) )  →  { ( 𝐼  +  1 ) }  ⊆  ( 1 ... 𝑁 ) ) | 
						
							| 26 |  | undif | ⊢ ( { ( 𝐼  +  1 ) }  ⊆  ( 1 ... 𝑁 )  ↔  ( { ( 𝐼  +  1 ) }  ∪  ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) )  =  ( 1 ... 𝑁 ) ) | 
						
							| 27 | 25 26 | sylib | ⊢ ( ( 𝑁  ∈  ℕ  ∧  𝐼  ∈  ( 1 ... ( 𝑁  −  1 ) ) )  →  ( { ( 𝐼  +  1 ) }  ∪  ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) )  =  ( 1 ... 𝑁 ) ) | 
						
							| 28 | 27 | feq2d | ⊢ ( ( 𝑁  ∈  ℕ  ∧  𝐼  ∈  ( 1 ... ( 𝑁  −  1 ) ) )  →  ( 𝑄 : ( { ( 𝐼  +  1 ) }  ∪  ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) ) ⟶ ℝ  ↔  𝑄 : ( 1 ... 𝑁 ) ⟶ ℝ ) ) | 
						
							| 29 | 23 28 | mpbii | ⊢ ( ( 𝑁  ∈  ℕ  ∧  𝐼  ∈  ( 1 ... ( 𝑁  −  1 ) ) )  →  𝑄 : ( 1 ... 𝑁 ) ⟶ ℝ ) | 
						
							| 30 |  | elee | ⊢ ( 𝑁  ∈  ℕ  →  ( 𝑄  ∈  ( 𝔼 ‘ 𝑁 )  ↔  𝑄 : ( 1 ... 𝑁 ) ⟶ ℝ ) ) | 
						
							| 31 | 30 | adantr | ⊢ ( ( 𝑁  ∈  ℕ  ∧  𝐼  ∈  ( 1 ... ( 𝑁  −  1 ) ) )  →  ( 𝑄  ∈  ( 𝔼 ‘ 𝑁 )  ↔  𝑄 : ( 1 ... 𝑁 ) ⟶ ℝ ) ) | 
						
							| 32 | 29 31 | mpbird | ⊢ ( ( 𝑁  ∈  ℕ  ∧  𝐼  ∈  ( 1 ... ( 𝑁  −  1 ) ) )  →  𝑄  ∈  ( 𝔼 ‘ 𝑁 ) ) |