## Abstract The basic theory of potentialβenergy tensors related to heterogeneous spheres is reviewed, and the special case of truncated, singular, isothermal spheres is examined in detail. Special effort is devoted to a system made of two isothermal spheres, one completely lying within the other,
The definable criterion for definability in Presburger arithmetic and its applications
β Scribed by An.A. Muchnik
- Publisher
- Elsevier Science
- Year
- 2003
- Tongue
- English
- Weight
- 131 KB
- Volume
- 290
- Category
- Article
- ISSN
- 0304-3975
No coin nor oath required. For personal study only.
β¦ Synopsis
In Section 1 of present paper we construct a formula 'n(A) of Presburger arithmetic (integers with addition and order) with additional n-ary predicate variable A. This formula is true if and only if predicate A is deΓΏnable in Presburger arithmetic (Theorem 2).
This formula is used to prove the following facts: (1) given a ΓΏnite synchronous automaton recognizing a set of n-tuples of integers written in positional notation one can e ectively decide whether this set is deΓΏnable in Presburger arithmetic; (2) every predicate (set of n-tuples of integers) recognizable in two essentially di erent positional systems is deΓΏnable in Presburger arithmetic. The last result was proved by Cobham (Math. Systems Theory, 3(2) (1969) 186) for the case n=1. In general case both (1) and (2) were proved by Semenov (Ph.D. Thesis, Moscow State University; Siberian Math. J. 18(2) (1977) 403) (Semenov's proofs are very di cult).
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