On the Lebesgue constant of subperiodic trigonometric interpolation

We solve a recent conjecture, proving that the Lebesgue constant of Chebyshev-like angular nodes for trigonometric interpolation on a subinterval [−ω,ω][−ω,ω] of the full period [−π,π][−π,π] is attained at ±ω±ω, and its value is independent of ωω and coincides with the Lebesgue constant of algebraic interpolation at the classical Chebyshev nodes in (−1,1)(−1,1).