Jacobi fields of the Tanaka-Webster connection on Sasakian manifolds

We build a variational theory of geodesics of the Tanaka-Webster connection on a strictly pseudoconvex CR manifold.Comment: 52 page

Subelliptic harmonic morphisms

We study subelliptic harmonic morphisms i.e. smooth maps $\phi: \Omega \to \tilde\Omega$ among domains $\Omega \subset \mathbb{R}^n$ and $\tilde\Omega \subset \mathbb{R}^M$ endowed with Hörmander systems of vector fields $X$ and $Y$, that pull back local solutions to $H_Y v = 0$ into local solutions to $H_X u = 0$, where $H_X$ and $H_Y$ are Hörmander operators. We show that any subelliptic harmonic morphism is an open mapping. Using a subelliptic version of the Fuglede-Ishihara theorem (due to E. Barletta [5]) we show that given a strictly pseudoconvex CR manifold $M$ and a Riemannian manifold $N$ for any heat equation morphism $\Psi: M \times (0, \infty) \to N \times (0, \infty)$ of the form $\Psi(x,t) = ( \phi (x), h(t))$ the map $\phi : M \to N$ is a subelliptic harmonic morphism

Applications et Morphismes Harmoniques

DoctoralCes leçons constituent une exposition precise, avec des calculs explicites, d elements introductifs a la theorie des applications harmoniques entre varietes Riemanniennes. On etablit les formules de la premiere et de la seconde variation de l'energie de Dirichlet et on montre certaines de leurs consequences geometriques comme le theoreme de B. Solomon (cf. [34]) et la theorie de la stabilite pour les applications harmoniques. On demontre aussi un theoreme classique de B. Fuglede et T. Ishihara (cf. [18], [23]) sur les morphismes harmoniques. Les morphismes des equations de la chaleur et les morphismes des noyaux de la chaleur (avec variables separees) sont decrits, dans la theorie des morphismes harmoniques, par un resultat tres beau de E. Loubea

Enhancement of seismic resistance of buildings

The objectives of the paper are both seismic instrumentation for damage assessment and enhancing of seismic resistance of buildings. In according with seismic design codes in force the buildings are designed to resist at seismic actions. Due to the time evolution of these design provisions, there are buildings that were designed decades ago, under the less stringent provisions. The conceptual conformation is nowadays provided in all Codes of seismic design. According to the Code of seismic design P100-1:2006 the asymmetric structures do not have an appropriate seismic configuration; they have disadvantageous distribution of volumes, mass and stiffness. Using results of temporary seismic instrumentation the safety condition of the building may be assessed in different phases of work. Based on this method, the strengthening solutions may be identified and the need of seismic joints may be emphasised. All the aforementioned ideas are illustrated through a case study. Therefore it will be analysed the dynamic parameter evolution of an educational building obtained in different periods. Also, structural intervention scenarios to enhance seismic resistance will be presented

On the continuity of the eigenvalues of a sublaplacian

International audienceWe study the behavior of the eigenvalues of a sublaplacian $\Delta_b$ on a compact strictly pseudoconvex CR manifold $M$, as functions on the set ${\mathcal P}_+$ of positively oriented contact forms on $M$ by endowing ${\mathcal P}_+$ with a natural metric topology

Yang-Mills fields on CR manifolds

We study pseudo Yang-Mills fields on a compact strictly pseudoconvex CR manifold.Comment: 52 page