# ANNALI DELL'UNIVERSITA' DI FERRARA

ANNALI DELL'UNIVERSITA' DI FERRARA > 2006 > 52 > 1 > 19-36

**S**has the form $\displaystyle \mathbf{S}=-P\mathbf{I}+\left( \mu (\theta )+\tau (\theta ){|\mathbf{D(u)}|}^{p(\theta )-2}\right) {\mathbf{D(u)}}, $ where

**u**is the vector velocity,

*P*is the pressure,

*θ*is the temperature and

*μ*,

*p*and

*τ*are the given coefficients...

ANNALI DELL'UNIVERSITA' DI FERRARA > 2006 > 52 > 1 > 107-126

*x*

^{ n }as a linear combination of the images of

*β*

_{ m }under the powers of the shift operator

*E*(here $\beta_m(x):=\frac{x^{\underline{m}}}{m!}$ ). We encode the coefficients of these linear combinations in a 3-dimensional array - the Eulerian octant - and we find recurrences formulæ, explicit expressions...

ANNALI DELL'UNIVERSITA' DI FERRARA > 2006 > 52 > 1 > 1-17

*γ*<2, in a domain defined by two levels of geopotential. Under the force due to geopotential and the Coriolis force, we prove the stability of the equilibrium state in a suitable Sobolev space.

*Keywords:*Viscous barotropic gas, Equilibrium state, Coriolis...

ANNALI DELL'UNIVERSITA' DI FERRARA > 2006 > 52 > 1 > 65-81

*Keywords:*Global hypoellipticity, Global solvability, Gevrey classes, Diophantine approximation...

ANNALI DELL'UNIVERSITA' DI FERRARA > 2006 > 52 > 1 > 137-172

*Ω*∈

*R*

^{ n }under the assumption that the initial value of the velocity vector field

**v**

_{0}belongs to

*C*

^{ s }(

*Ω*), $s\in [0,2)$ (in particular, it can be only continuous). The solution is obtained in some weighted Hölder spaces. This result makes it possible to prove the local solvability of a nonlinear problem under...

ANNALI DELL'UNIVERSITA' DI FERRARA > 2006 > 52 > 1 > 53-64

*Keywords:*Nonlinear parabolic-elliptic system of degenerate type, Periodic solutions, Thermistor problem

*Mathematics Subject Classification (2000):*...

ANNALI DELL'UNIVERSITA' DI FERRARA > 2006 > 52 > 1 > 99-106

*G*, is nilpotent, but different from

*Φ*(

*G*). Further, if is a saturated formation and if $\,\mathcal{F}(G)\,$ is the intersection of all maximal subgroups of

*G*not belonging to , a necessary and sufficient condition is given...

ANNALI DELL'UNIVERSITA' DI FERRARA > 2006 > 52 > 1 > 83-87

*Keywords:*Polar coordinates, Tangent vector, Inner product

*Mathematics Subject Classification (2000):*34A12

ANNALI DELL'UNIVERSITA' DI FERRARA > 2006 > 52 > 1 > 127-135

ANNALI DELL'UNIVERSITA' DI FERRARA > 2006 > 52 > 1 > 45-51

*Keywords:*Liouville numbers, Infinite series

*Mathematics Subject Classification (2000):*11J82

ANNALI DELL'UNIVERSITA' DI FERRARA > 2006 > 52 > 1 > 37-43

*Keywords:*Waring problem, Partially symmetric tensor, Segre-Veronese embedding, Noether-Fano inequality, Weakly defective variety

*Mathematics Subject Classification (2000):*...

ANNALI DELL'UNIVERSITA' DI FERRARA > 2006 > 52 > 1 > 89-97

*Keywords:*Hyperbolic plane, Quasi-regular quadrangle, Pseudo-parallelogram, Hypercycle, Hypocycle

*Mathematics Subject Classification (2000):*20N05

ANNALI DELL'UNIVERSITA' DI FERRARA > 2006 > 52 > 2 > 189-197

*f*from the Heisenberg group into itself, provided the Pansu differential of

*f*is continuous, non singular and satisfies some growth conditions at infinity. An estimate for the Lipschitz constant (with respect to the Carnot–Carathéodory distance in ) of a continuously Pansu differentiable map is included. This gives a characterization of...

ANNALI DELL'UNIVERSITA' DI FERRARA > 2006 > 52 > 2 > 199-209

*t*=0. On the other hand, the equation is weakly hyperbolic...

ANNALI DELL'UNIVERSITA' DI FERRARA > 2006 > 52 > 2 > 211-232

**Keywords:**Decay estimates, Fourier...

ANNALI DELL'UNIVERSITA' DI FERRARA > 2006 > 52 > 2 > 271-280

**Keywords:**Cauchy problem, Evolution equations, Loss of regularity of the solution

ANNALI DELL'UNIVERSITA' DI FERRARA > 2006 > 52 > 2 > 291-301

**Keywords:**Traffic flows, Hyperbolic conservatin laws, Operator splitting method

ANNALI DELL'UNIVERSITA' DI FERRARA > 2006 > 52 > 2 > 371-382

ANNALI DELL'UNIVERSITA' DI FERRARA > 2006 > 52 > 2 > 233-246

*R*

_{ χ }(

*λ*) =

*χ*(–

*Δ*

_{ D }–

*λ*

^{2})

^{–1}

*χ*, where

*Δ*

_{ D }is the Laplacian with Dirichlet boundary condition and $\chi \in C_0^{\infty}(\mathbb{R}^n)$ equal to 1 in a neighborhood of the obstacle

*K*. We show that if

*R*

_{ χ }(

*λ*) has no...

ANNALI DELL'UNIVERSITA' DI FERRARA > 2006 > 52 > 2 > 431-456

**Keywords:**Clustering theorems, Periodic trajectories, Poisson...