Aproksymacje nilpotentne w analizie nieholonomicznej - postępy i trudności w podejściu wielomianowym

Speaker(s)

Piotr Mormul

Affiliation

Uniwersytet Warszawski

Date

Nov. 20, 2015, 10:15 a.m.

Room

room 5840

Seminar

Seminar of Dynamical Systems Group

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It was Gianna Stefani who - in her Bierutowice 1984 talk - first started to look for something simpler than the canonical exponential coordinates of the 1st or 2nd kind. Then she used her finding to locally simplify the control systems linear in control - to define a prototype of the nilpotent approximation (NA in short) of the initial system.
Agrachev&Sarychev joined in in 1987, Hermes&Kawski in 1991, Risler in 1992, Bellaiche in 1996. That last contributor proposed an algorithm, of improving a given set of local coordinates to privileged (or: adapted) ones, that was purely polynomial, avoiding any exponentiation. In a sense, Bellaiche debugged Stefani's original approach of 1984. A polished version of his procedure will be reproduced during the talk, along with a series of remarks on desirable further improvements and/or shortcuts aimed at getting eventually a workable algorithm.

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