abstract

It is emphasized that Einstein’s theory of gravitation has its physical and logical roots, firstly, in Newton’s theory, namely in the existence of Newtonian tidal forces, and, secondly, in the requirement that these forces be compatible with the theory of relativity. Furthermore, it is pointed out that the nonexistence of any covariant description of energy in Einstein’s theory is deeply rooted in a local ‘unindentifiability’ of the gravitational force in Newton’s theory, although this fact is irrelevant in that theory.

abstract

This lecture was delivered by the author of the book “Konin: A Quest”, which describes the history of the Jewish community in the small town of Konin in central Poland. Unable at that time to find employment in any university in Poland, Leopold Infeld served there as headmaster of a Jewish co-educational high school between 1922 and 1924. Drawing on his own researches as well as Infeld’s memoir “Quest: The Evolution of a Scientist”, the author presents Infeld within the context of his family’s social and religious background, and his “exile” years as a teacher in Konin, evoking a little-known period in the scientist’s life.

abstract

This is only a summary of a lecture delivered at the Infeld Centenial Meeting. In the lecture the history of the Born–Infeld nonlinear electrodynamics was presented and some general features of the theory were discussed.

abstract

On the basis of material in the Einstein Archive and Infeld’s writings, the story of their relationship between 1920 and 1955 is reconstructed. While the scientific side of their early contacts and later collaboration is discussed, the major emphasis is placed on the development of their personal relations, and their comments on various social, cultural and political questions.

abstract

A comparative analysis of two different versions of the Legendre transformation is presented. A complete geometric background for this analysis is provided. Examples of applications to a number of physical systems are given.

abstract

This article is an extended outline of the lecture delivered at the Infeld Centenial Meeting. In the lecture a review was given of the development of the theory of spinors and related objects in special and general relativity, with some emphasis on the twistor theory and its implications. The lecture was not intended as a detailed account of the subject, but it rather was a series of comments on the relevance of various spinor-type objects and their relation to some features of space-time structure. The present article is also a guide, with its author’s personal preferences, to the extensive bibliography of the subject.

abstract

In this talk a brief survey has been carried out on the development of cosmology from the days Leopold Infeld was active in the field up to the present. Attention in particular is paid to the history of our knowledge of Hubble’s expansion, of the cosmological constant, of the average density of matter and its distribution, and of the related issue of possible types of matter in the Universe.

abstract

Reminiscences of Leopold Infeld as a teacher, a school builder, a writer and a political figure are presented by a former pupil. Also described is his little-known pioneering contribution to antenna theory.

abstract

We investigate the cosmological model with the complex scalar self-interacting inflaton field non-minimally coupled to gravity. The different geometries of the Euclidean classically forbidden regions are represented. The instanton solutions of the corresponding Euclidean equations of motion are found by numerical calculations supplemented by the qualitative analysis of Lorentzian and Euclidean trajectories. The applications of these solutions to the no-boundary and tunneling proposals for the wave function of the Universe are studied. Possible interpretation of obtained results and their connection with inflationary cosmology is discussed.