Titlebook: Differential Geometry and Relativity; A Volume in Honour o M. Cahen,M. Flato Book 1976 D. Reidel Publishing Company, Dordrecht, Holland 197

progestin

The Scalar Curvaturebe: Does there exist a conformal metric for which the scalar curvature is constant? And also problems posed by Chern, Nirenberg and others. All these problems are almost entirely solved, however there remain some open questions (see the conjectures).

充足

Some Relations between Volume, Injectivity Radius, and Convexity Radius in Riemannian Manifolds .(.). The present article studies the following problems: do there exist universal constants .(.), .(.) such that .(.)≥.(.)..(.), .(.)≥.(.)..(.) for every riemannian manifold of dimension .? An affirmative answer is given to the second problem for any . but with an unsharp constant; an affirmative

熔巖

CHAFE

Some Remarks on the Fundamental Kernels of a Pseudo-Riemannian Manifolde review some results and problems concerning these solutions; in particular their relations with the geometry and analysis on the manifold (. and .. kernels) are considered. Professor Lichnerowicz’s work has greatly inspired this paper. We wish to present it to him as a mark of our heartiest thanks

FIS

On Lie Transformation Groups and the Covariance of Differential Operatorssics, we were led to study the actions of a group of transformations of a manifold . (the space-time in general relativity) on the sections of a vector bundle over . (the tensor or spinor fields of a given type). Several equivalent characterizations of these actions are given. A similar study is mad

legitimate

Geometrical Interpretations of Scalar Curvature and Regularity of Conformal Homeomorphismsprove that every conformal homeomorphism of .. manifolds is of .. class. Up to now, it seems that this result has been proved only in the euclidean case by Y. G. Resetnyak [7] and F. W. Gehring [3]. We plan in this paper to solve the general case by a method analogous to the one of Resetnyak.

Infraction

adequate-intake

Mobility in Categories and Metric Spacesfollows originated in attempts to understand the notions of . and . for bodies in space, it turns out that the ‘mobile’ and ‘comobile’ morphisms that we define occur throughout mathematics. Indeed, they are to be found in any categories between which there is a pair of adjoint functors.

BIDE

The Tension Field of Maps of Riemannian Manifolds the mapping is an isometry, the tension field becomes none other than the mean curvature vector field. A harmonic map is one for which the tension field is zero, so that an isometric harmonic map has zero mean curvature, i.e. the image is a minimal surface. Considerable interest has been shown duri

COM

Thirty Years of Activity in the Renovation of Mathematical Educationman of the French ministerial committee for mathematical education, chairman of the national committee of the I.R.E.M.s (Instituts de Recherche sur l’Enseignement Mathématique) since their creation (1968).