اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدShock waves for the Burgers equation and curvatures of diffeomorphism groups
95
0
0.0
(
0
)
تأليف
Boris Khesin
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We establish a simple relation between curvatures of the group of volume-preserving diffeomorphisms and the lifespan of potential solutions to the inviscid Burgers equation before the appearance of shocks. We show that shock formation corresponds to a focal point of the group of volume-preserving diffeomorphisms regarded as a submanifold of the full diffeomorphism group and, consequently, to a conjugate point along a geodesic in the Wasserstein space of densities. This establishes an intrinsic connection between ideal Euler hydrodynamics (via Arnolds approach), shock formation in the multidimensional Burgers equation and the Wasserstein geometry of the space of densities.
قيم البحث
اقرأ أيضاً
In this note we obtain the characterization for asymptotic directions on various subgroups of the diffeomorphism group. We give a simple proof of non-existence of such directions for area-preserving diffeomorphisms of closed surfaces of non-zero curv
ature. Finally, we exhibit the common origin of the Monge-Ampere equations in 2D fluid dynamics and mass transport.
We consider the Cauchy problem for the Burgers hierarchy with general time dependent coefficients. The closed form for the Greens function of the corresponding linear equation of arbitrary order $N$ is shown to be a sum of generalised hypergeometric
functions. For suitably damped initial conditions we plot the time dependence of the Cauchy problem over a range of $N$ values. For $N=1$, we introduce a spatial forcing term. Using connections between the associated second order linear Schr{o}dinger and Fokker-Planck equations, we give closed form expressions for the corresponding Greens functions of the sinked Bessel process with constant drift. We then apply the Greens function to give time dependent profiles for the corresponding forced Burgers Cauchy problem.
By studying the Higgs bundle equations with the gauge group replaced by the group of symplectic diffeomorphisms of the 2-sphere we encounter the notion of a folded hyperkaehler 4-manifold and conjecture the existence of a family of such metrics param
etrised by an infinite-dimensional analogue of Teichmueller space.
Let $X$ be a compact orientable non-Haken 3-manifold modeled on the Thurston geometry $text{Nil}$. We show that the diffeomorphism group $text{Diff}(X)$ deformation retracts to the isometry group $text{Isom}(X)$. Combining this with earlier work by m
any authors, this completes the determination the homotopy type of $text{Diff}(X)$ for any compact, orientable, prime 3-manifold $X$.
We complete the proof of the Generalized Smale Conjecture, apart from the case of $RP^3$, and give a new proof of Gabais theorem for hyperbolic 3-manifolds. We use an approach based on Ricci flow through singularities, which applies uniformly to sphe
rical space forms other than $S^3$ and $RP^3$ and hyperbolic manifolds, to prove that the moduli space of metrics of constant sectional curvature is contractible. As a corollary, for such a 3-manifold $X$, the inclusion $text{Isom} (X,g)to text{Diff}(X)$ is a homotopy equivalence for any Riemannian metric $g$ of constant sectional curvature.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
