| Step | Hyp | Ref | Expression | 
						
							| 1 |  | axlowdimlem10.1 | ⊢ 𝑄  =  ( { 〈 ( 𝐼  +  1 ) ,  1 〉 }  ∪  ( ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } )  ×  { 0 } ) ) | 
						
							| 2 | 1 | fveq1i | ⊢ ( 𝑄 ‘ ( 𝐼  +  1 ) )  =  ( ( { 〈 ( 𝐼  +  1 ) ,  1 〉 }  ∪  ( ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } )  ×  { 0 } ) ) ‘ ( 𝐼  +  1 ) ) | 
						
							| 3 |  | ovex | ⊢ ( 𝐼  +  1 )  ∈  V | 
						
							| 4 |  | 1ex | ⊢ 1  ∈  V | 
						
							| 5 | 3 4 | fnsn | ⊢ { 〈 ( 𝐼  +  1 ) ,  1 〉 }  Fn  { ( 𝐼  +  1 ) } | 
						
							| 6 |  | c0ex | ⊢ 0  ∈  V | 
						
							| 7 | 6 | fconst | ⊢ ( ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } )  ×  { 0 } ) : ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) ⟶ { 0 } | 
						
							| 8 |  | ffn | ⊢ ( ( ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } )  ×  { 0 } ) : ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) ⟶ { 0 }  →  ( ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } )  ×  { 0 } )  Fn  ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) ) | 
						
							| 9 | 7 8 | ax-mp | ⊢ ( ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } )  ×  { 0 } )  Fn  ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) | 
						
							| 10 |  | disjdif | ⊢ ( { ( 𝐼  +  1 ) }  ∩  ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) )  =  ∅ | 
						
							| 11 | 3 | snid | ⊢ ( 𝐼  +  1 )  ∈  { ( 𝐼  +  1 ) } | 
						
							| 12 | 10 11 | pm3.2i | ⊢ ( ( { ( 𝐼  +  1 ) }  ∩  ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) )  =  ∅  ∧  ( 𝐼  +  1 )  ∈  { ( 𝐼  +  1 ) } ) | 
						
							| 13 |  | fvun1 | ⊢ ( ( { 〈 ( 𝐼  +  1 ) ,  1 〉 }  Fn  { ( 𝐼  +  1 ) }  ∧  ( ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } )  ×  { 0 } )  Fn  ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } )  ∧  ( ( { ( 𝐼  +  1 ) }  ∩  ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } ) )  =  ∅  ∧  ( 𝐼  +  1 )  ∈  { ( 𝐼  +  1 ) } ) )  →  ( ( { 〈 ( 𝐼  +  1 ) ,  1 〉 }  ∪  ( ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } )  ×  { 0 } ) ) ‘ ( 𝐼  +  1 ) )  =  ( { 〈 ( 𝐼  +  1 ) ,  1 〉 } ‘ ( 𝐼  +  1 ) ) ) | 
						
							| 14 | 5 9 12 13 | mp3an | ⊢ ( ( { 〈 ( 𝐼  +  1 ) ,  1 〉 }  ∪  ( ( ( 1 ... 𝑁 )  ∖  { ( 𝐼  +  1 ) } )  ×  { 0 } ) ) ‘ ( 𝐼  +  1 ) )  =  ( { 〈 ( 𝐼  +  1 ) ,  1 〉 } ‘ ( 𝐼  +  1 ) ) | 
						
							| 15 | 3 4 | fvsn | ⊢ ( { 〈 ( 𝐼  +  1 ) ,  1 〉 } ‘ ( 𝐼  +  1 ) )  =  1 | 
						
							| 16 | 2 14 15 | 3eqtri | ⊢ ( 𝑄 ‘ ( 𝐼  +  1 ) )  =  1 |