A formal quantifier elimination for algebraically

We introduce the notions of open-closed field algebra and open-closed field algebra over a vertex operator algebra V. In the case that V satisfies certain finiteness and reductivity conditions, we show that an open-closed field algebra over V canonically gives an algebra over a C-extension of Swiss

1. In this paper we wish to study fields which can be written as inter-sections of real closed fields. Several more restrictive classes of fields have received careful study (real closed fields by Artin and Schreier, hered-itarily euclidean fields by Prestel and Ziegler [8], hereditarily Pythago

Algebraic closure In the previous lecture, we have seen how to “force ” the existence of prime ideals, even in a weark framework where we don’t have choice axiom Instead of “forcing ” the existence of a point of a space (a mathematical object), we are going to “force ” the existence of a model (a mathematical structure)

We investigate the combinatorial geometry obtained from algebraic closure over a fixed subfield in an algebraically closed field. The main result classifies the subgeometries which are isomorphic to projective planes. This is applied to give new examples of algebraic characteristic sets of matroids

Jan Krajicek posed the following problem: Is there is a generalization result in the theory of real closed fields of the form: If A(1 + ... + 1) (n occurrences of 1) is provable in length k for all n, then (x)A(x) is provable? It is argued that the answer to this question depends on the particular

Abstract. We consider the groups which are infinitely definable in separably closed fields of finite degree of imperfection. We prove in particular that no new definable groups arise in this way: we show that any group definable in such a field L is definably isomorphic to the group of L

Abstract. We show that for any real number, the class of real numbers less random than it, in the sense of rK-reducibility, forms a countable real closed subfield of the real ordered field. This generalizes the well-known fact that the computable reals form a real closed field. With the same

Fix an algebraically closed field k. Let Mg be the moduli space of curves of genus g over k. The main result of this note is that Mg is irreducible for every k. Of course, whether or not M s is irreducible depends only on the characteristic of k. When the characteristic s o, we can assume that k

We consider the theory (ACFp)P of pairs F < K of algebraically closed fields of a given characteristic p. We exhibit a collection of additional sorts in which this theory has geometric elimination of imaginaries. The sorts are essentially of the form ∪ a∈B(F)Va(K)/Ga(F), where G, V, B