We study the stability of the optimal stopping problem for a discrete-time Markov process on a general space state X. Revenue and cost functions are allowed to be unbounded. The stability (robustness) is understood in the sense that an unknown transition probability p(·|x), x ∈ X, is approximated by the known one p̃(·|x), x ∈ X, and the stopping rule τ̃∗, optimal for the process governed by p̃ is ...

we classify the paracontact riemannian manifolds that their rieman-nian curvature satisfies in the certain condition and we show that thisclassification is hold for the special cases semi-symmetric and locally sym-metric spaces. finally we study paracontact riemannian manifolds satis-fying r(x, ξ).s = 0, where s is the ricci tensor.

‎We present streamlined proofs of certain maximality principles studied by Hamkins‎ ‎and Woodin‎. ‎Moreover‎, ‎we formulate an intermediate maximality principle‎, ‎which is‎ ‎shown here to be equiconsistent with the existence of a weakly compact cardinal $kappa$ such that $V_{kappa}prec V$‎.

1. The activation energy for the hydrolytic breaking of a peptid linkage has been calculated from quantum mechanical considerations. 2. The relative catalytic effects of H(+) and OH(-) and the mechanism of these effects have been calculated and discussed. 3. These effects are both qualitatively and semiquantitatively in agreement with experiment.

In this paper we study the spectra of certain classes of Room frames. The three spectra which we study are incomplete Room squares, uniform Room frames and Room frames of type 2t. These problems have been studied in numerous papers over the years; in this paper, we complete the three spectra. In addition we find a Howell cube of type H3(6, 10). This corrects a previous claim of nonexistence of ...