Weight systems for toric Calabi-Yau varieties and reflexivity of Newton polyhedra

According to a recently proposed scheme for the classification of reflexive polyhedra, weight systems of a certain type play a prominent role. These weight systems are classified for the cases $n=3$ and $n=4$, corresponding to toric varieties with K3 and Calabi--Yau hypersurfaces, respectively. For $n=3$ we find the well known 95 weight systems corresponding to weighted \IP^3's that allow transverse polynomials, whereas for $n=4$ there are 184026 weight systems, including the 7555 weight systems for weighted \IP^4's. It is proven (without computer) that the Newton polyhedra corresponding to all of these weight systems are reflexive.Comment: Latex, 14 page

Flavour Mixing and Fermion Mass Generation as a Result of Symmetry Breaking

It is shown that a simple breaking of the subnuclear democracy leads to a successful description of the mixing between the second and third family. In the lepton channel the $\nu _{\mu } - \nu_{\tau }$ oscillations are expected to be described by a mixing angle of $2.65^ {\circ }$ which might be observed soon in neutrino experiments.Comment: 9 pages, report MPI-PHT/94-2

A Grammatical Inference Approach to Language-Based Anomaly Detection in XML

False-positives are a problem in anomaly-based intrusion detection systems. To counter this issue, we discuss anomaly detection for the eXtensible Markup Language (XML) in a language-theoretic view. We argue that many XML-based attacks target the syntactic level, i.e. the tree structure or element content, and syntax validation of XML documents reduces the attack surface. XML offers so-called schemas for validation, but in real world, schemas are often unavailable, ignored or too general. In this work-in-progress paper we describe a grammatical inference approach to learn an automaton from example XML documents for detecting documents with anomalous syntax. We discuss properties and expressiveness of XML to understand limits of learnability. Our contributions are an XML Schema compatible lexical datatype system to abstract content in XML and an algorithm to learn visibly pushdown automata (VPA) directly from a set of examples. The proposed algorithm does not require the tree representation of XML, so it can process large documents or streams. The resulting deterministic VPA then allows stream validation of documents to recognize deviations in the underlying tree structure or datatypes.Comment: Paper accepted at First Int. Workshop on Emerging Cyberthreats and Countermeasures ECTCM 201

Flavor Mixing, CP-Violation and the Masses ov the Light Quarks

The observed hierarchy of the quark masses is interpreted as a signal for an underlying ``subnuclear democracy'' as the relevant symmetry of the quark mass terms. A simple breaking of the symmetry leads to a mixing between the second and the third family, in agreement with observation. Introducing the mixing between the first and the second family, one finds an interesting pattern of maximal CP--violation as well as a complete determination of the elements of the CKM matrix and of the unitarity triangle.Comment: 7 page