Stable definability and generic relations

نویسندگان
چکیده

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Stable definability and generic relations

An amalgamation base p in a simple theory is stably definable if its canonical base is interdefinable with the set of canonical parameters for the φ-definitions of p as φ ranges through all stable formulae. A necessary condition for stably definability is given and used to produce an example of a supersimple theory with stable forking having types that are not stably definable. This answers neg...

متن کامل

Generalized Rational Relations and their Logical Definability

The family of rational subsets of a direct product of free monoids Σ∗ 1×. . .×Σ ∗ n (the rational relations) is not closed under Boolean operations, except when n = 1 or when all Σi’s are empty or singletons. In this paper we introduce the family of generalized rational subsets of an arbitrary monoid as the closure of the singletons under the Boolean operations, concatenation and Kleene star (j...

متن کامل

Modal Definability Based on Łukasiewicz Validity Relations

We study two notions of definability for classes of relational structures based on modal extensions of Łukasiewicz finitely-valued logics. The main results of the paper are the equivalent of the Goldblatt Thomason theorem for these notions of definability.

متن کامل

Definability of Combinatorial Functions and Their Linear Recurrence Relations

We consider functions of natural numbers which allow a combinatorial interpretation as density functions (speed) of classes of relational structures, such as Fibonacci numbers, Bell numbers, Catalan numbers and the like. Many of these functions satisfy a linear recurrence relation over Z or Zm and allow an interpretation as counting the number of relations satisfying a property expressible in M...

متن کامل

Lambda Definability with Sums via Grothendieck Logical Relations

We introduce a notion of Grothendieck logical relation and use it to characterise the deenability of morphisms in stable bicartesian closed categories by terms of the simply-typed lambda calculus with nite products and nite sums. Our techniques are based on concepts from topos theory, however our exposition is elementary.

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

ژورنال

عنوان ژورنال: Journal of Symbolic Logic

سال: 2007

ISSN: 0022-4812,1943-5886

DOI: 10.2178/jsl/1203350778