Logic » Finite Model Theory

Order-invariant queries ★★

Author(s): Segoufin

Question  
    \item Does $ {<}\text{-invariant\:FO} = \text{FO} $ hold over graphs of bounded tree-width? \item Is $ {<}\text{-invariant\:FO} $ included in $ \text{MSO} $ over graphs? \item Does $ {<}\text{-invariant\:FO} $ have a 0-1 law? \item Are properties of $ {<}\text{-invariant\:FO} $ Hanf-local? \item Is there a logic (with an effective syntax) that captures $ {<}\text{-invariant\:FO} $?

Keywords: Effective syntax; FMT12-LesHouches; Locality; MSO; Order invariance

Posted by dberwanger
updated May 18th, 2012
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Logic » Finite Model Theory

Fixed-point logic with counting ★★

Author(s): Blass

Question   Can either of the following be expressed in fixed-point logic plus counting:
    \item Given a graph, does it have a perfect matching, i.e., a set $ M $ of edges such that every vertex is incident to exactly one edge from $ M $? \item Given a square matrix over a finite field (regarded as a structure in the natural way, as described in [BGS02]), what is its determinant?

Keywords: Capturing PTime; counting quantifiers; Fixed-point logic; FMT03-Bedlewo

Posted by dberwanger
updated May 18th, 2012
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Number Theory

Birch & Swinnerton-Dyer conjecture ★★★★

Author(s):

Conjecture   Let $ E/K $ be an elliptic curve over a number field $ K $. Then the order of the zeros of its $ L $-function, $ L(E, s) $, at $ s = 1 $ is the Mordell-Weil rank of $ E(K) $.

Keywords:

Posted by eyoong
updated May 12th, 2012
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