Systems with distributions and viability theorem
  The approach to the consideration of the ordinary differential equations with distributions in the classical space $\mathcal D'$ of distributions with continuous test functions has certain insufficiencies: the notations are incorrect from the point of view of distribution theory, the right-hand side has to satisfy the restrictive conditions of equality type. In the present paper we consider an initial value problem for the ordinary differential equation with distributions in the space of distributions with dynamic test functions $\mathcal T'$, where the continuous operation of multiplication of distributions by discontinuous functions is defined, and show that this approach does not have the aforementioned insufficiencies.   We provide the sufficient conditions for viability of solutions of the ordinary differential equations with distributions (a generalization of the Nagumo Theorem), and show that the consideration of the distributional (impulse) controls in the problem for avoidance of encounters with the set (the maximal viability time problem) allows us to provide the existence of solution, which may not exist for the ordinary controls. 
D. Kinzebulatov