---

Step * of Lemma count-pos-iff

∀[A:Type]. ∀P:A ⟶ 𝔹. ∀L:A List.  ((∃x∈L. ↑(P x)) ⇐⇒ 0 < count(P;L))
BY
{ (InstLemma `length-filter-pos-iff` [] THEN RepeatFor 3 (ParallelLast') THEN RWO "count-length-filter" 0⋅ THEN Auto) }

---

Latex:

---

Latex:
\mforall{}[A:Type].  \mforall{}P:A  {}\mrightarrow{}  \mBbbB{}.  \mforall{}L:A  List.    ((\mexists{}x\mmember{}L.  \muparrow{}(P  x))  \mLeftarrow{}{}\mRightarrow{}  0  <  count(P;L))


By

---

Latex:
(InstLemma  `length-filter-pos-iff`  []
  THEN  RepeatFor  3  (ParallelLast')
  THEN  RWO  "count-length-filter"  0\mcdot{}
  THEN  Auto)

---

Home Index