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] of the full period [−π, π] is attained at ±ω, its value is independent of ω and coincides with the Lebesgue constant of algebraic interpolation at the classical Chebyshev nodes in (−1, 1). 2000 AMS subject classification: 42A15, 65T40.