2 Search Results for "Jones, Lee"


Document
An Intuitionistic Analysis of Size-change Termination

Authors: Silvia Steila

Published in: LIPIcs, Volume 39, 20th International Conference on Types for Proofs and Programs (TYPES 2014)


Abstract
In 2001 Lee, Jones and Ben-Amram introduced the notion of size-change termination (SCT) for first order functional programs, a sufficient condition for termination. They proved that a program is size-change terminating if and only if it has a certain property which can be statically verified from the recursive definition of the program. Their proof of the size-change termination theorem used Ramsey's Theorem for pairs, which is a purely classical result. In 2012 Vytiniotis, Coquand and Wahlsteldt intuitionistically proved a classical variant of the size-change termination theorem by using the Almost-Full Theorem instead of Ramsey's Theorem for pairs. In this paper we provide an intuitionistic proof of another classical variant of the SCT theorem: our goal is to provide a statement and a proof very similar to the original ones. This can be done by using the H-closure Theorem, which differs from Ramsey's Theorem for pairs only by a contrapositive step. As a side result we obtain another proof of the characterization of the functions computed by a tail-recursive SCT program, by relating the SCT Theorem with the Termination Theorem by Podelski and Rybalchenko. Finally, by investigating the relationship between them, we provide a property in the "language" of size-change termination which is equivalent to Podelski and Rybalchenko's termination.

Cite as

Silvia Steila. An Intuitionistic Analysis of Size-change Termination. In 20th International Conference on Types for Proofs and Programs (TYPES 2014). Leibniz International Proceedings in Informatics (LIPIcs), Volume 39, pp. 288-307, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2015)


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@InProceedings{steila:LIPIcs.TYPES.2014.288,
  author =	{Steila, Silvia},
  title =	{{An Intuitionistic Analysis of Size-change Termination}},
  booktitle =	{20th International Conference on Types for Proofs and Programs (TYPES 2014)},
  pages =	{288--307},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-88-0},
  ISSN =	{1868-8969},
  year =	{2015},
  volume =	{39},
  editor =	{Herbelin, Hugo and Letouzey, Pierre and Sozeau, Matthieu},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.TYPES.2014.288},
  URN =		{urn:nbn:de:0030-drops-55026},
  doi =		{10.4230/LIPIcs.TYPES.2014.288},
  annote =	{Keywords: Intuitionism, Ramsey's Theorem, Termination}
}
Document
Local Minimax Learning of Approximately Polynomial Functions

Authors: Lee Jones and Konstantin Rybnikov

Published in: Dagstuhl Seminar Proceedings, Volume 6201, Combinatorial and Algorithmic Foundations of Pattern and Association Discovery (2006)


Abstract
Suppose we have a number of noisy measurements of an unknown real-valued function $f$ near point of interest $mathbf{x}_0 in mathbb{R}^d$. Suppose also that nothing can be assumed about the noise distribution, except for zero mean and bounded covariance matrix. We want to estimate $f$ at $mathbf{x=x}_0$ using a general linear parametric family $f(mathbf{x};mathbf{a}) = a_0 h_0 (mathbf{x}) ++ a_q h_q (mathbf{x})$, where $mathbf{a} in mathbb{R}^q$ and $h_i$'s are bounded functions on a neighborhood $B$ of $mathbf{x}_0$ which contains all points of measurement. Typically, $B$ is a Euclidean ball or cube in $mathbb{R}^d$ (more generally, a ball in an $l_p$-norm). In the case when the $h_i$'s are polynomial functions in $x_1,ldots,x_d$ the model is called locally-polynomial. In particular, if the $h_i$'s form a basis of the linear space of polynomials of degree at most two, the model is called locally-quadratic (if the degree is at most three, the model is locally-cubic, etc.). Often, there is information, which is called context, about the function $f$ (restricted to $B$ ) available, such as that it takes values in a known interval, or that it satisfies a Lipschitz condition. The theory of local minimax estimation with context for locally-polynomial models and approximately locally polynomial models has been recently initiated by Jones. In the case of local linearity and a bound on the change of $f$ on $B$, where $B$ is a ball, the solution for squared error loss is in the form of ridge regression, where the ridge parameter is identified; hence, minimax justification for ridge regression is given together with explicit best error bounds. The analysis of polynomial models of degree above 1 leads to interesting and difficult questions in real algebraic geometry and non-linear optimization. We show that in the case when $f$ is a probability function, the optimal (in the minimax sense) estimator is effectively computable (with any given precision), thanks to Tarski's elimination principle.

Cite as

Lee Jones and Konstantin Rybnikov. Local Minimax Learning of Approximately Polynomial Functions. In Combinatorial and Algorithmic Foundations of Pattern and Association Discovery. Dagstuhl Seminar Proceedings, Volume 6201, pp. 1-12, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2007)


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@InProceedings{jones_et_al:DagSemProc.06201.3,
  author =	{Jones, Lee and Rybnikov, Konstantin},
  title =	{{Local Minimax Learning of Approximately Polynomial Functions}},
  booktitle =	{Combinatorial and Algorithmic Foundations of Pattern and Association Discovery},
  pages =	{1--12},
  series =	{Dagstuhl Seminar Proceedings (DagSemProc)},
  ISSN =	{1862-4405},
  year =	{2007},
  volume =	{6201},
  editor =	{Rudolf Ahlswede and Alberto Apostolico and Vladimir I. Levenshtein},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/DagSemProc.06201.3},
  URN =		{urn:nbn:de:0030-drops-8912},
  doi =		{10.4230/DagSemProc.06201.3},
  annote =	{Keywords: Local learning, statistical learning, estimator, minimax, convex optimization, quantifier elimination, semialgebraic, ridge regression, polynomial}
}
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