theorem
proved
term proof
sound_speed_positive
show as:
view Lean formalization →
formal statement (Lean)
44theorem sound_speed_positive (R : ℝ) (hR : -1 < R) :
45 0 < sound_speed R := by
proof body
Term-mode proof.
46 unfold sound_speed
47 apply div_pos one_pos
48 apply Real.sqrt_pos_of_pos
49 linarith
50
51/-- In the limit R → 0 (radiation dominated): c_s → c/√3. -/