Spencer Operator and Applications: From Continuum Mechanics to Mathematical physics
Abstract
The Spencer operator, introduced by D.C. Spencer fifty years ago, is rarely used in mathematics today and, up to our knowledge, has never been used in engineering applications or mathematical physics. The main purpose of this paper, an extended version of a lecture at the second workshop on Differential Equations by Algebraic Methods (DEAM2, february 9-11, 2011, Linz, Austria) is to prove that the use of the Spencer operator constitutes the common secret of the three following famous books published about at the same time in the beginning of the last century, though they do not seem to have anything in common at first sight as they are successively dealing with elasticity theory, commutative algebra, electromagnetism and general relativity: (C) E. and F. COSSERAT: "Th\'eorie des Corps D\'eformables", Hermann, Paris, 1909. (M) F.S. MACAULAY: "The Algebraic Theory of Modular Systems", Cambridge University Press, 1916. (W) H. WEYL: "Space, Time, Matter", Springer, Berlin, 1918 (1922, 1958; Dover, 1952). Meanwhile, we shall point out the importance of (M) for studying control identifiability and of (C)+(W) for the group theoretical unification of finite elements in engineering sciences, recovering in a purely mathematical way well known field-matter coupling phenomena (piezzoelectricity, photoelasticity, streaming birefringence, viscosity, ...). As a byproduct and though disturbing it could be, we shall prove that these unavoidable new diferential and homological methods contradict the mathematical foundations of both engineering (continuum mechanics,electromagnetism) and mathematical (gauge theory, general relativity) physics.
Keywords
Cite
@article{arxiv.1102.4916,
title = {Spencer Operator and Applications: From Continuum Mechanics to Mathematical physics},
author = {Jean-François Pommaret},
journal= {arXiv preprint arXiv:1102.4916},
year = {2011}
}
Comments
Though a few of the results presented are proved in the recent references provided, the way they are combined with others and patched together around the three books quoted is new. In view of the importance of the full paper, the present version is only a summary of the definitive version to appear later on. Finally, the reader must not forget that "each formula" appearing in this new general framework has been used explicitly or implicitly in (C), (M) and (W) for a mechanical, mathematical or physical purpose