A subset of which is a finite Boolean combination of sets of the form and , where .

**References**

Bierstone, E. and Milman, P. ``Semialgebraic and Subanalytic Sets.'' *IHES Pub. Math.* **67**, 5-42, 1988.

Marker, D. ``Model Theory and Exponentiation.'' *Not. Amer. Math. Soc.* **43**, 753-759, 1996.

© 1996-9

1999-05-26