68 research outputs found

    Controllability and Qualitative properties of the solutions to SPDEs driven by boundary L\'evy noise

    Full text link
    Let uu be the solution to the following stochastic evolution equation (1) du(t,x)& = &A u(t,x) dt + B \sigma(u(t,x)) dL(t),\quad t>0; u(0,x) = x taking values in an Hilbert space \HH, where LL is a \RR valued L\'evy process, A:HHA:H\to H an infinitesimal generator of a strongly continuous semigroup, \sigma:H\to \RR bounded from below and Lipschitz continuous, and B:\RR\to H a possible unbounded operator. A typical example of such an equation is a stochastic Partial differential equation with boundary L\'evy noise. Let \CP=(\CP_t)_{t\ge 0} %{\CP_t:0\le t<\infty}thecorrespondingMarkoviansemigroup.Weshowthat,ifthesystem(2)du(t)=Au(t)dt+Bv(t),t>0u(0)=xisapproximatecontrollableintime the corresponding Markovian semigroup. We show that, if the system (2) du(t) = A u(t)\: dt + B v(t),\quad t>0 u(0) = x is approximate controllable in time T>0,thenundersomeadditionalconditionson, then under some additional conditions on Band and A,forany, for any x\in Htheprobabilitymeasure the probability measure \CP_T^\star \delta_xispositiveonopensetsof is positive on open sets of H.Secondly,asanapplication,weinvestigateunderwhichconditionon. Secondly, as an application, we investigate under which condition on %\HHandontheLeˊvyprocess and on the L\'evy process Landontheoperator and on the operator Aand and B$ the solution of Equation [1] is asymptotically strong Feller, respective, has a unique invariant measure. We apply these results to the damped wave equation driven by L\'evy boundary noise

    On some stages of development of research in the field of magnetism

    No full text

    Das wellenförmige Fließen dünner Schichten einer viskosen Flüssigkeit. 1. Der freie Fluss

    No full text
    Das Fließen dünner Schichten einer viskosen Flüssigkeit unter dem Einfluß der Massenkraft bei Berücksichtigung der Oberflächenspannung wurde theoretisch untersucht. Gefunden wurde die näherungsweise Lösung einer Strömungsgleichung, die angibt, daß der von einigen Verfassern festgestellte wellenförmige Zustand stabiler ist als der laminare. Die Form des Wellenprofils, die Phasengeschwindigkeit und die Amplitude wurden ermittelt. Die gefundenen theoretischen Größen der kritischen Werte Re(kr), bei denen der Wellenzustand eintritt, stimmen mit dem Experiment überein. Durch die wellenförmige Art der Strömung konnte die von Friedman und Miller beobachtete schnelle Farbausbreitung längs des flüssigen Stromes quantitativ bestimmt werden

    On some stages of development of research in the field of magnetism

    No full text

    the Purification and Properties of Pectin Methyl Esterase from Cladosporium Herbarum (Pers.) Link.

    No full text
    Cladosporium herbarum (Pers.) Link is an Imperfect Fungus found abundantly in the soil. It is generally saprophytic, rarely parasitic, and probably its main role in the natural environment is to assist in the decomposition of vegetable matter. Its spores are most abundant in the atmosphere being present in every location tested so far by Pady and Kelly (1953, 1954) and Kelly and Pady (1953). [...

    To some principles of creative upbringing and education of present youth

    No full text
    corecore