English
Two paths are equal if all their components (edges and vertices) are equal; extensionality principle.
Русский
Два пути равны, если равны все их компоненты (вершины и ребра); принцип экстенсивности.
LaTeX
$$$\\forall f,g : X.Path(m), (\\forall i, f.arrow i = g.arrow i) \\Rightarrow f = g$$$
Lean4
/-- A path of length `n` in a simplicial set `X` is defined as a 1-truncated
path in the 1-truncation of `X`. -/
abbrev Path (X : SSet.{u}) (n : ℕ) :=
truncation 1 |>.obj X |>.Path n