theorem
proved
tactic proof
entangled_higher_cost
show as:
view Lean formalization →
formal statement (Lean)
57theorem entangled_higher_cost (N : ℕ) (hN : N > 1) (j_single α : ℝ) (hα : α > 0) :
58 jcostEntangled N j_single α > jcostProduct N j_single := by
proof body
Tactic-mode proof.
59 unfold jcostEntangled jcostProduct
60 -- Need: N * j_single + α * N * (N - 1) / 2 > N * j_single
61 -- Simplifies to: α * N * (N - 1) / 2 > 0
62 have hN_pos : (N : ℝ) > 0 := Nat.cast_pos.mpr (by omega)
63 have hN_m1_pos : (N : ℝ) - 1 > 0 := by
64 have : N ≥ 2 := hN
65 have h : (N : ℝ) ≥ 2 := Nat.cast_le.mpr this
66 linarith
67 have h_extra_pos : α * ↑N * (↑N - 1) / 2 > 0 := by positivity
68 linarith
69
70/-- **THEOREM**: The cost difference scales as N². -/