منابع مشابه
An Extended Lachlan Splitting Theorem
We show that the top of any diamond with bottom 0 in the r.e. degrees is also the top of a stack of n diamonds with bottom 0. Let R be the upper semilattice of the recursively enumerable degrees. A minimal pair consists of two incomparable r.e. degrees with innmum equal to the recursive degree 0. An r.e. degree is cappable if it is one half of a minimal pair. An r.e. degree a is the top of a di...
متن کاملOn a Theorem of Lachlan and Martin
In [3] we raised the following question: does there exist a recursively enumerable degree d such that 0(n)<d(n)<0(n+1) for all wjSO? This question was answered affirmatively by Lachlan [l] and by Martin [2]. Lachlan's proof combines a familiar priority argument with the fixed point theorem of Kleene. Martin's proof is a new form of priority argument based on Theorem 3 of section 6 of [3]. In th...
متن کاملOn the distribution of Lachlan nonsplitting bases
We say that a computably enumerable (c.e.) degree b is a Lachlan nonsplitting base (LNB), if there is a computably enumerable degree a such that a > b, and for any c.e. degrees w,v ≤ a, if a ≤ w ∨ v ∨ b then either a ≤ w ∨ b or a ≤ v ∨ b. In this paper we investigate the relationship between bounding and nonbounding of Lachlan nonsplitting bases and the high /low hierarchy. We prove that there ...
متن کاملM M O-b D S
We propose an alternative characterisation of object-based distributed systems in terms of algebraic structures and topological spaces. Some examples are given in order to attest the adequacy of this approach to the subject. We also illustrate a method of transference of results from these mathematical theories that can further contribute to the advancement of distributed systems theory.
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his study was carried out to determine the importance of type 2 Diabetes mellitus as a risk factor for osteoporosis in postmenopausal women. Materials and Methods: This study was conducted in 2004 on 40 diabetic and 40 healthy postmenopausal women attending the endocrine clinics in Zanjan. These two groups were matched in terms of age, length of their menopausal period and body mass index. Seru...
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ژورنال
عنوان ژورنال: Journal of Applied Crystallography
سال: 2010
ISSN: 0021-8898
DOI: 10.1107/s0021889810035971