For , any distinct node set in different from the Chebyshev polynomial extrema admits one degree- polynomial , bounded by one at all those nodes, whose every nonconstant derivative violates the corresponding sharp endpoint bound. In decreasing order set . The endpoint derivative signs of Lagrange cardinal polynomials give . Interpolating on the same nodes shows
Each term is nonnegative and at least one is positive, because the other node set includes a nonextremal point. Uniqueness is a claim about node sets: permuting the same nodes does not change their norming property.

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