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Count tested index occurrences

Lax342547.FilterOccurrences · concepts/Lax342547/FilterOccurrences.lean · lax-342547

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    Natural Language Statement

    Lemma

    Filtering subtype indices and filtering their underlying finite set have identical cardinalities.

    Concept map
    14 concepts
    100%
    Proven claimThis conceptRelated conceptA → B: B builds on ADescendants are omitted for concepts with more than 10 descendants.
    Evidence

    Each proof establishes this claim relative to its assumptions.

    Lean source view on GitHub

    1import Lax342547.CoverCounts
    2
    3/-!
    4---
    5title: Count tested index occurrences
    6type: lemma
    7---
    8Filtering subtype indices and filtering their underlying finite set have identical cardinalities.
    9-/
    10
    11namespace Lax342547.FilterOccurrences
    12
    13
    14
    15axiom filter_subtype_card {ι : Type} [DecidableEq ι] (I : Finset ι) (P : ι → Prop) : by
    16 classical
    17 exact (Finset.univ.filter (fun i : I => P i.val)).card = (I.filter P).card
    18
    19end Lax342547.FilterOccurrences
    20
    Show Proof
    Builds on
    Used by
    From Mathlib

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