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Hilbert's 13th Problem

Objective

The aim of this fellowship is to enable Dr Christopher Good, as Scientist in Charge, and Dr Ziqin Feng, as Researcher, to carry out some innovative and mutually beneficial research utilizing their complementary skill sets.

The 13th Problem from Hilbert's famous list asks whether every continuous (respectively smooth) function of three variables can be written as a superposition (or, in modern parlance, composition) of continuous (respectively smooth) functions of two variables. Hilbert conjectured that the answer to this problem was `no.' However, in 1957, Kolmogorov together with his student Arnold gave a positive solution in the continuous case: every continuous function of n variables taken from the closed unit interval can be represented as a linear superposition of one-variable functions and the two-variable function addition. One might expect this result to have applications (for example to data analysis), since it allows for multi-dimensional functions to be expressed as `simpler' functions of one variable and addition. However, whilst being of great theoretical interest, Kolmogorov's result is highly non-constructive and does not obviously allow for this. Together with Professor Paul Gartside, Feng has made highly non-trivial extensions to Kolmogorov's theorem that suggest ways around these restrictions. This project aims to realize potential applications by providing improved algorithms, implementing the extensions in high-level computer code.
Vitushkin gave a negative answer to the smooth (differentiable) version of Hilbert's 13th problem in 1954, proving, in particular, that there are continuously differentiable functions of three variables which can not be written as a superposition of continuously differentiable functions of two variables. The project also aims to investigate just how smooth one can take the functions arising in Kolmogorov's theorem to be. Questions along these lines will be addressed through combinatorical analysis of Vitushkin's work, the topology of critical points, and approximation theory in function spaces.

Call for proposal

FP7-PEOPLE-2011-IIF
See other projects for this call

Coordinator

THE UNIVERSITY OF BIRMINGHAM
EU contribution
€ 209 033,40
Address
Edgbaston
B15 2TT Birmingham
United Kingdom

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Region
West Midlands (England) West Midlands Birmingham
Activity type
Higher or Secondary Education Establishments
Administrative Contact
May Chung (Ms.)
Links
Total cost
No data