theorem
proved
term proof
gamma_ge_one
show as:
view Lean formalization →
formal statement (Lean)
40theorem gamma_ge_one (v c : ℝ) (hc : 0 < c) (hv : |v| < c) :
41 1 ≤ c / Real.sqrt (c^2 - v^2) := by
proof body
Term-mode proof.
42 rw [le_div_iff (Real.sqrt_pos.mpr (by nlinarith [sq_nonneg v, sq_abs v, abs_lt.mp hv]))]
43 rw [one_mul]
44 apply Real.le_sqrt.mpr
45 constructor
46 · positivity
47 · nlinarith [sq_abs v, abs_lt.mp hv]
48
49/-- J-cost at rapidity: J(cosh θ) = cosh θ - 1 = γ - 1 ≥ 0. -/