We consider solutions to the hyperbolic system of equations of ideal granular
hydrodynamics with conserved mass, total energy and finite momentum of inertia
and prove that these solutions generically lose the initial smoothness within a
finite time in any space dimension $n$ for the adiabatic index $\gamma \le
1+\frac{2}{n}.$ Further, in the one-dimensional case we introduce a solution
depending only on the spatial coordinate outside of a ball containing the
origin and prove that this solution under rather general assumptions on initial
data cannot be global in time too.
We present an explicit hedging strategy, which enables to prove arbitrageness
of market incorporating at least two assets depending on the same random
factor. The implied Black-Scholes volatility, computed taking into account the
form of the graph of the option price, related to our strategy, demonstrates
the "skewness" inherent to the observational data.
We study the dependence of volatility on the stock price in the stochastic
volatility framework on the example of the Heston model.To be more specific, we
consider the conditional expectation of variance (square of volatility) under
fixed stock price return as a function of the return and time. The behavior of
this function depends on the initial stock price return distribution density.
In particular, we obtain the "smile" effect near the mean value of the stock
price return.
We consider a generalization of the compressible barotropic Navier-Stokes
equations to the case of non-Newtonian fluid in the whole space. The viscosity
tensor is assumed to be coercive with an exponent $q>1.$ We prove that if the
total mass and momentum of the system are conserved, then one can find a
constant $q_0>1$ depending on the dimension of space $n$ and the heat ratio
$\gamma$ such that for $q\in [q_0,n)$ there exists no global in time smooth
solution to the Cauchy problem.
Using a method of stochastic perturbation of a Langevin system associated
with the non-viscous Burgers equation we construct a solution to the Riemann
problem for the pressureless gas dynamics describing sticky particles dynamics.
As a bridging step we consider a medium consisting of noninteracting particles.
We analyze the difference in the behavior of discontinuous solutions for these
two models and the relations between them. In our framework in 1D case we
obtain a unique entropy solution to the Riemann problem.