Step
*
of Lemma
finite-decidable-subset
∀T:Type. ∀B:T ⟶ ℙ. (finite(T)
⇒ (∀x:T. Dec(↓B[x]))
⇒ finite({t:T| B[t]} ))
BY
{ (Auto THEN (InstLemma `equipollent-split` [⌜T⌝;⌜B⌝]⋅ THENA Auto)) }
1
1. T : Type
2. B : T ⟶ ℙ
3. finite(T)
4. ∀x:T. Dec(↓B[x])
5. T ~ {x:T| B[x]} + {x:T| ¬B[x]}
⊢ finite({t:T| B[t]} )
Latex:
Latex:
\mforall{}T:Type. \mforall{}B:T {}\mrightarrow{} \mBbbP{}. (finite(T) {}\mRightarrow{} (\mforall{}x:T. Dec(\mdownarrow{}B[x])) {}\mRightarrow{} finite(\{t:T| B[t]\} ))
By
Latex:
(Auto THEN (InstLemma `equipollent-split` [\mkleeneopen{}T\mkleeneclose{};\mkleeneopen{}B\mkleeneclose{}]\mcdot{} THENA Auto))
Home
Index