Step |
Hyp |
Ref |
Expression |
1 |
|
wrdnfi |
⊢ ( 𝑆 ∈ Fin → { 𝑎 ∈ Word 𝑆 ∣ ( ♯ ‘ 𝑎 ) = 𝑇 } ∈ Fin ) |
2 |
|
upwordisword |
⊢ ( 𝑎 ∈ UpWord 𝑆 → 𝑎 ∈ Word 𝑆 ) |
3 |
2
|
ad2antrl |
⊢ ( ( ⊤ ∧ ( 𝑎 ∈ UpWord 𝑆 ∧ ( ♯ ‘ 𝑎 ) = 𝑇 ) ) → 𝑎 ∈ Word 𝑆 ) |
4 |
3
|
rabss3d |
⊢ ( ⊤ → { 𝑎 ∈ UpWord 𝑆 ∣ ( ♯ ‘ 𝑎 ) = 𝑇 } ⊆ { 𝑎 ∈ Word 𝑆 ∣ ( ♯ ‘ 𝑎 ) = 𝑇 } ) |
5 |
4
|
mptru |
⊢ { 𝑎 ∈ UpWord 𝑆 ∣ ( ♯ ‘ 𝑎 ) = 𝑇 } ⊆ { 𝑎 ∈ Word 𝑆 ∣ ( ♯ ‘ 𝑎 ) = 𝑇 } |
6 |
|
ssfi |
⊢ ( ( { 𝑎 ∈ Word 𝑆 ∣ ( ♯ ‘ 𝑎 ) = 𝑇 } ∈ Fin ∧ { 𝑎 ∈ UpWord 𝑆 ∣ ( ♯ ‘ 𝑎 ) = 𝑇 } ⊆ { 𝑎 ∈ Word 𝑆 ∣ ( ♯ ‘ 𝑎 ) = 𝑇 } ) → { 𝑎 ∈ UpWord 𝑆 ∣ ( ♯ ‘ 𝑎 ) = 𝑇 } ∈ Fin ) |
7 |
5 6
|
mpan2 |
⊢ ( { 𝑎 ∈ Word 𝑆 ∣ ( ♯ ‘ 𝑎 ) = 𝑇 } ∈ Fin → { 𝑎 ∈ UpWord 𝑆 ∣ ( ♯ ‘ 𝑎 ) = 𝑇 } ∈ Fin ) |
8 |
1 7
|
syl |
⊢ ( 𝑆 ∈ Fin → { 𝑎 ∈ UpWord 𝑆 ∣ ( ♯ ‘ 𝑎 ) = 𝑇 } ∈ Fin ) |