Membership in the selected distance class (corrected)
ProvedBatch3N9.Problem97.mem_selectedClass_fixed_v3A point belongs to the selected distance class exactly when it belongs to the finite set and is at the selected distance from the source point.
Preamble
import Mathlib.Geometry.Euclidean.Angle.Oriented.Basic import Mathlib.Geometry.Euclidean.Sphere.Basic import Mathlib.Analysis.InnerProductSpace.PiL2 import Mathlib.Data.Real.Basic import Definitions.Def_SelectedClass open scoped EuclideanGeometry Real open Batch3N9 open Problem97
Formal statement
theorem Batch3N9.Problem97.mem_selectedClass_fixed_v3 {A : Finset (EuclideanSpace ℝ (Fin 2))} {s : EuclideanSpace ℝ (Fin 2)} {d : ℝ} {q : EuclideanSpace ℝ (Fin 2)} :
q ∈ Batch3N9.Problem97.SelectedClass A s d ↔ q ∈ A ∧ dist s q = d := by sorrySource