English
For a nontrivial s, infsep(s) equals the infimum over all unordered pairs in s.
Русский
Для неабстрактного s инфsep(s) равен наименьшему (infi) по всем неординарным парам внутри s.
LaTeX
$$$ s.Nontrivial \rightarrow s.infsep = \big \wedge_{d\in s.offDiag} (dist d) $$$
Lean4
theorem infsep_triple (hxy : x ≠ y) (hyz : y ≠ z) (hxz : x ≠ z) :
({ x, y, z } : Set α).infsep = dist x y ⊓ dist x z ⊓ dist y z := by
simp only [infsep, einfsep_triple hxy hyz hxz, ENNReal.toReal_inf, edist_ne_top x y, edist_ne_top x z,
edist_ne_top y z, dist_edist, Ne, inf_eq_top_iff, and_self_iff, not_false_iff]