Olga Rozanova

  1. Formation of singularities in solutions to ideal hydrodynamics of freely cooling inelastic gases.

    Authors: Olga Rozanova
    Subjects: Analysis of PDEs
    Abstract

    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.

  2. Arbitrage hedging strategy and one more explanation of the volatility smile.

    Authors: Olga Rozanova, Mikhail Martynov
    Subjects: Pricing of Securities
    Abstract

    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.

  3. On dependence of the implied volatility on returns for stochastic volatility models.

    Authors: Olga Rozanova, Mikhail Martynov
    Subjects: Pricing of Securities
    Abstract

    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.

  4. Nonexistence results for compressible non-Newtonian fluid with magnetic effects in the whole space.

    Authors: Olga Rozanova
    Subjects: Analysis of PDEs
    Abstract

    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.

  5. Probabilistic model associated with the pressureless gas dynamics.

    Authors: Sergio Albeverio, Anastasia Korshunova, Olga Rozanova
    Subjects: Analysis of PDEs
    Abstract

    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.

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