We provide sufficient conditions for the continuity of the free-boundary in a general class of finite-horizon optimal stopping problems arising for instance in finance and economics. The underlying process is a strong solution of one-dimensional, time-homogeneous stochastic differential equation (SDE). The proof relies on both analytic and probabilistic arguments and it is based on a contradict...

We propose a modal logic that enables us to handle self-referential formulae, including ones with negative selfreferences, which on one hand, would introduce a logical contradiction, namely Russell’s paradox, in the conventional setting, while on the other hand, are necessary to capture a certain class of programs such as fixed point combinators and objects with so-called binary methods in obje...

This paper proposes a modal typing system that enables us to handle self-referential formulae, including ones with negative self-references, which on one hand, would introduce a logical contradiction, namely Russell’s paradox, in the conventional setting, while on the other hand, are necessary to capture a certain class of programs such as fixed-point combinators and objects with so-called bina...

Abstract We study in a quark model the contradiction between factorization and duality found in nonleptonic decays at next to leading order in 1/Nc, concentrating on quark exchange mechanism. The contradiction originates in the fact that the standard factorization assumption approximates the asymptotic final states by a non-orthogonal set of states, thus leading to an overcounting of the decay ...

Real clocks are not perfect. This must have an effect in our predictions for the behavior of a quantum system, an effect for which we present a unified description, encompassing several previous proposals. We study the relevance of clock errors in the Zeno effect and find that generically no Zeno effect can be present ~in such a way that there is no contradiction with currently available experi...

One can prove X1 is not regular using the pumping lemma. One can prove X2 is not regular either by using the pumping lemma (a version with bounds on the prefix) or by contradiction: if X2 is regular than X2 ∩ a∗b∗ = X1 is regular. One cannot prove X3 non-regular with the pumping theorem directly; however one can prove its regular by contradiction: if X3 is regular than X3 = X2 is regular. We wi...

In a recent paper, de Freitas et al. [Phys. Rev. E 61, 6330 (2000)] presented simulational results for the critical exponents of the two-species reaction-diffusion system A+B-->2B and B-->A in dimension d=1. In particular, the correlation length exponent was found as nu=2.21(5) in contradiction to the well-known relation nu=2/d. In this Comment, the symmetry arguments leading to exact critical ...