106,009 research outputs found
Ricci flow coupled with harmonic map flow
No full text07.02.13 KB. Accepted version ok to add to Spiral. SMF/SherpaWe investigate a new geometric flow which consists of a coupled system of the Ricci flow on a closed manifold M with the harmonic map flow of a map phi from M to some closed target manifold N with a (possibly time-dependent) positive coupling constant alpha. This system can be interpreted as the gradient flow of an energy functional F_alpha which is a modification of Perelman's energy F for the Ricci flow, including the Dirichlet energy for the map phi. Surprisingly, the coupled system may be less singular than the Ricci flow or the harmonic map flow alone. In particular, we can always rule out energy concentration of phi a-priori - without any assumptions on the curvature of the target manifold N - by choosing alpha large enough. Moreover, if alpha is bounded away from zero it suffices to bound the curvature of (M,g(t)) to also obtain control of phi and all its derivatives - a result which is clearly not true for alpha = 0. Besides these new phenomena, the flow shares many good properties with the Ricci flow. In particular, we can derive the monotonicity of an entropy functional W_alpha similar to Perelman's Ricci flow entropy W and of so-called reduced volume functionals. We then apply these monotonicity results to rule out non-trivial breathers and geometric collapsing at finite times
L-optimal transportation for Ricci flow
No full textWe introduce the notion of L-optimal transportation, and use it to construct a natural monotonic quantity for Ricci flow which includes a selection of other monotonicity results, including some key discoveries of Perelman [13] (both related to entropy and to L-length) and a recent result of McCann and the author [11]
On Type-I singularities in Ricci flow
No full text07.02.13 KB. Accepted version ok to add to Spiral. IP/Sherpa.We define several notions of singular set for Type I Ricci flows and show that they all coincide. In order to do this, we prove that blow-ups around singular points converge to nontrivial gradient shrinking solitons, thus extending work of Naber. As a by-product we conclude that the volume of a finite-volume singular set vanishes at the singular time. We also define a notion of density for Type I Ricci flows and use it to prove a regularity theorem reminiscent of White's partial regularity result for mean curvature flow
Studying the bancassurance phenomenon: A two side analysis on the relevant case of Italy
No full textF. RICCI,Luoghi e non luoghi di partecipazione politica nell’agorà digitale: simulacri e virtualità delle istituzioni .
No full textIl modo in cui interroghiamo il mondo e la realtà ci dà la possibilità di comprenderne il senso e la direzione.
E dunque, riflettere sui vari aspetti e le implicazioni connesse alla democrazia diretta nell’era digitale, dalla mia prospettiva filosofica significa soprattutto rovesciare l’arazzo, cercare i nodi profondi della tessitura, saperne interrogare i punti di torsione: analizzare i modi in cui gli individui danno forma e significato al proprio mondo, e a loro stessi come cittadini nell’ambiente sociale in cui vivono, è una via per decifrare la grammatica profonda attraverso cui costruiamo e percepiamo la realtà di cui siamo parte.
Parto, quindi, da una prima questione: quali strutture del pensiero sono capaci di dare un senso e un ordine all’universo dell’era digitale, e scoprirne gli schemi costitutivi che garantiscano la leggibilità del mondo? E soprattutto, ha ancora senso porre questo interrogativo
Studying the bancassurance phenomenon: An empirical exploratory analysis on a European sample
No full textf– Kenmotsu Metric as Conformal Ricci Soliton
No full textIn this paper, we study conformal Ricci solitons in f- Kenmotsu manifolds. We derive conditions for f-Kenmotsu metric to be a conformal Ricci soliton
f– Kenmotsu Metric as Conformal Ricci Soliton
No full textAbstract
In this paper, we study conformal Ricci solitons in f- Kenmotsu manifolds. We derive conditions for f-Kenmotsu metric to be a conformal Ricci soliton.</jats:p
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