6,527 research outputs found
Cross-Lingual Adaptation using Structural Correspondence Learning
Cross-lingual adaptation, a special case of domain adaptation, refers to the
transfer of classification knowledge between two languages. In this article we
describe an extension of Structural Correspondence Learning (SCL), a recently
proposed algorithm for domain adaptation, for cross-lingual adaptation. The
proposed method uses unlabeled documents from both languages, along with a word
translation oracle, to induce cross-lingual feature correspondences. From these
correspondences a cross-lingual representation is created that enables the
transfer of classification knowledge from the source to the target language.
The main advantages of this approach over other approaches are its resource
efficiency and task specificity.
We conduct experiments in the area of cross-language topic and sentiment
classification involving English as source language and German, French, and
Japanese as target languages. The results show a significant improvement of the
proposed method over a machine translation baseline, reducing the relative
error due to cross-lingual adaptation by an average of 30% (topic
classification) and 59% (sentiment classification). We further report on
empirical analyses that reveal insights into the use of unlabeled data, the
sensitivity with respect to important hyperparameters, and the nature of the
induced cross-lingual correspondences
Automorphisms of Higher Rank Lamplighter Groups
Let denote the group whose Cayley graph with respect to a
particular generating set is the Diestel-Leader graph , as described
by Bartholdi, Neuhauser and Woess. We compute both and
for , and apply our results to count twisted
conjugacy classes in these groups when . Specifically, we show that
when , the groups have property , that is,
every automorphism has an infinite number of twisted conjugacy classes. In
contrast, when the lamplighter groups have property if and only if .Comment: 28 page
On chvátal's conjecture related to a hereditary system
AbstractIt is shown that among the maximal intersecting systems, which are subsystems of a hereditary family F, there is a star, as claimed by a conjecture of Chvátal, if it is assumed, that the number of bases of F is n, but n-1 bases of F form a simple-star
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