On the conditioning of polynomial histopolation

Ludovico Bruni Bruno; Stefano Serra-Capizzano

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arXiv · 2511.15395

On the conditioning of polynomial histopolation

Ludovico Bruni Bruno·Stefano Serra-Capizzano

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Abstract

Histopolation is the approximation procedure that associates a degree $ d-1 $ polynomial $ p_{d-1} \in \mathscr{P}_{d-1} (I) $ with a locally integrable function $ f $ imposing that the integral (or, equivalently, the average) of $p$ coincides with that of $f$ on a collection of $ d $ distinct segments $s_i$. In this work we discuss unisolvence and conditioning of the associated matrices, in an asymptotic linear algebra perspective, i.e., when the matrix-size $d$ tends to infinity. While the unisolvence is a rather sparse topic, the conditioning in the unisolvent setting has a uniform behavior: as for the case of standard Vandermonde matrix-sequences with real nodes, the conditioning is inherently exponential as a function of $d$ when the monomial basis is chosen. In contrast, for an appropriate selection of supports, the Chebyshev polynomials of second kind exhibit a bounded conditioning. A linear behavior is also observed in the Frobenius norm.

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Ludovico Bruni Bruno, Stefano Serra-Capizzano. 2026-03-25. On the conditioning of polynomial histopolation. https://arxiv.org/abs/2511.15395

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