The tangent bundle of -velocities over a homogeneous space
The tangent space and the arcwise tangent space to a differential space
The tangent stars of a set, and extensions of smooth functions.
The topological complexity of sets of convex differentiable functions.
Let C(X) be the set of all convex and continuous functions on a separable infinite dimensional Banach space X, equipped with the topology of uniform convergence on bounded subsets of X. We show that the subset of all convex Fréchet-differentiable functions on X, and the subset of all (not necessarily equivalent) Fréchet-differentiable norms on X, reduce every coanalytic set, in particular they are not Borel-sets.
The topology of integrable differential forms near a singularity
The topology of the Yang-Mills theory over torus
The torsion of spinor connections and related structures.
The total divergence equation.
The trace of the generalized harmonic oscillator
We study a geometric generalization of the time-dependent Schrödinger equation for the harmonic oscillatorwhere is the Laplace-Beltrami operator with respect to a “scattering metric” on a compact manifold with boundary (the class of scattering metrics is a generalization of asymptotically Euclidean metrics on , radially compactified to the ball) and is a perturbation of , with a boundary defining function for (e.g. in the compactified Euclidean case). Using the quadratic-scattering...
The transmission property.
The two-dimensional eikonal equation.
The Tzitzeica surface as solution of PDE systems.
The unfoldings of a germ of vector fields in the plane with a singularity of codimension 3
The uniqueness for minimal surfaces in S3.
The universal order one invariant of framed knots in most -bundles over orientable surfaces.
The use of Cerami sequences in critical point theory.
The verification of the Nirenberg-Treves conjecture
In a series of recent papers, Nils Dencker proves that condition implies the local solvability of principal type pseudodifferential operators (with loss of derivatives for all positive ), verifying the last part of the Nirenberg-Treves conjecture, formulated in 1971. The origin of this question goes back to the Hans Lewy counterexample, published in 1957. In this text, we follow the pattern of Dencker’s papers, and we provide a proof of local solvability with a loss of derivatives.
The versality discriminant and local topological equivalence of mappings
We will extend the infinitesimal criteria for the equisingularity (i.e. topological triviality) of deformations of germs of mappings , , to non-finitely determined germs (these occur generically outside the “nice dimensions” for Mather, even among topologically stable mappings). The failure of finite determinacy is described geometrically by the “versality discriminant”, which is the set of points where is not stable (i.e. viewed as an unfolding it is not versal). The criterion asserts that...
The vertical prolongation of the projectable connections
We prove that any first order F2 Mm1,m2,n1,n2-natural operator transforming projectable general connections on an (m1,m2, n1, n2)-dimensional fibred-fibred manifold p = (p, p) : (pY : Y → Y) → (pM : M → M) into general connections on the vertical prolongation V Y → M of p: Y → M is the restriction of the (rather well-known) vertical prolongation operator V lifting general connections Γ on a fibred manifold Y → M into VΓ (the vertical prolongation of Γ) on V Y → M.
The Wave Group and Radiation Fields on Asymptotically Hyperbolic Manifolds