منابع مشابه
ω-rewriting the Collatz problem
The Collatz problem is comprised of two distinct, separate questions: existence of eventually periodic Collatz reductions with a nontrivial period, and existence of period-free Collatz reductions. This paper introduces a few distinct, related formalizations of the Collatz dynamics as term rewriting systems, using elementary concepts from the theory of state transition dynamics. Some of the subj...
متن کاملThe ω-Regular Post Embedding Problem
Post’s Embedding Problem is a new variant of Post’s Correspondence Problem where words are compared with embedding rather than equality. It has been shown recently that adding regular constraints on the form of admissible solutions makes the problem highly non-trivial, and relevant to the study of lossy channel systems. Here we consider the infinitary version and its application to recurrent re...
متن کاملThe isomorphism problem for ω-automatic trees
The main result of this paper is that the isomorphism for ω-automatic trees of finite height is at least has hard as second-order arithmetic and therefore not analytical. This strengthens a recent result by Hjorth, Khoussainov, Montalbán, and Nies [9] showing that the isomorphism problem for ω-automatic structures is not Σ 2 . Moreover, assuming the continuum hypothesis CH, we can show that the...
متن کاملAssessing the aerodynamic effects of tail elongations
Of the three species of Hirundine that breed sympatrically across the U.K., one, the 23 barn swallow, has outer tail feathers elongated into streamers, whereas the other two species, the 24
متن کامل2 00 7 Non - thermal right - handed sneutrino dark matter and the Ω DM / Ω b problem
We argue that the superpartner of the Dirac right-handed neutrino is a prime candidate for dark matter created from a ’mattergenesis’ mechanism. We show that due to the smallness of the Yukawa couplings, a right-handed sneutrino density created in the early Universe would not be erased by annihilations, which remain out of thermal equilibrium. It would also not be drowned by a later, additional...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Pacific Journal of Mathematics
سال: 1986
ISSN: 0030-8730,0030-8730
DOI: 10.2140/pjm.1986.121.121