theorem
proved
tactic proof
not_costDivergent_of_charge_zero
show as:
view Lean formalization →
formal statement (Lean)
327theorem not_costDivergent_of_charge_zero (sensor : DefectSensor)
328 (hzero : sensor.charge = 0) :
329 ¬ CostDivergent sensor := by
proof body
Tactic-mode proof.
330 intro hdiv
331 obtain ⟨N, hN⟩ := hdiv 1
332 let mesh : AnnularMesh N := uniformChargeMesh N sensor.charge
333 have hcost : 1 < annularCost mesh := by
334 exact hN mesh (by intro n; rfl)
335 have hexcess_zero : annularExcess mesh = 0 := by
336 simpa [mesh, hzero] using uniformChargeMesh_excess_zero N sensor.charge
337 have hfloor_zero : annularTopologicalFloor N mesh.charge = 0 := by
338 simpa [mesh, hzero] using (annularTopologicalFloor_zero N)
339 have hcost_zero : annularCost mesh = 0 := by
340 unfold annularExcess at hexcess_zero
341 rw [hfloor_zero] at hexcess_zero
342 linarith
343 have hfalse : ¬ (1 < (0 : ℝ)) := by norm_num
344 exact hfalse (by simpa [hcost_zero] using hcost)
345
346/-- Any cost-divergent sensor must have nonzero charge. -/