This paper is primarily
concerned with the theory of the arithmetic isolic integers. The following results are
obtained:
(1) No nonfinite member of the arithmetic isolic integers Λ∗(A) can be defined in
Λ∗(A) even by an infinite number of arithmetic formulas (Theorem 4).
(2) The arithmetic isols Λ(A) cannot be defined in Λ∗(A) even by an infinite
number of arithmetic formulas (Theorem 7).
(3) We exhibit some nonstandard models of arithmetic contained within Λ∗(A)
(Theorem 10).
The first result above follows from recent work of Nerode in the theory
of isols, while the second strengthens his results to obtain the desired
conclusion.
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