(**********)
Axiom
  G_pos :
    forall t : R, (0 <= t)%R -> (t < 2 / rho (vi intr))%R -> (0 <= G t)%R.

Theorem YCNGSTYS : forall t : R, (0 <= t)%R -> (rho (vi intr) * t < 2)%R -> (2 * r (vi intr) * sin (rho (vi intr) * (t / 2)) <= sqrt (Rsqr (xi intr t - xi intr 0) + Rsqr (yi intr t - yi intr 0)))%R.