Theorems · Theorem · algebraic topology

SSet.mem_degenerate_iff

∀ (X : SSet) {n : ℕ} (x : X.obj (Opposite.op { len := n })),
  x ∈ X.degenerate n ↔
    ∃ m,
      ∃ (_ : m < n),
        ∃ f, ∃ (_ : CategoryTheory.Epi f), x ∈ Set.range ⇑(CategoryTheory.ConcreteCategory.hom (X.map f.op))

Defined in

Mathlib.AlgebraicTopology.SimplicialSet.Degenerate

Cited by

2 results in Mathlib

Foundations

Depth 82 from the axioms · uses propext, Classical.choice, Quot.sound