18,415 research outputs found
A groupoid approach to noncommutative T-duality
Topological T-duality is a transformation taking a gerbe on a principal torus
bundle to a gerbe on a principal dual-torus bundle. We give a new geometric
construction of T-dualization, which allows the duality to be extended in
following two directions. First, bundles of groups other than tori, even
bundles of some nonabelian groups, can be dualized. Second, bundles whose duals
are families of noncommutative groups (in the sense of noncommutative geometry)
can be treated, though in this case the base space of the bundles is best
viewed as a topological stack.
Some methods developed for the construction may be of independent interest.
These are a Pontryagin type duality that interchanges commutative principal
bundles with gerbes, a nonabelian Takai type duality for groupoids, and the
computation of certain equivariant Brauer groups.Comment: Same theorems, typos correcte
Historical Amnesia: British and U.S. Intelligence, Past and Present
Many intelligence scandals in the news today seem unprecedented - from Russian meddling in the 2016 U.S. Presidential election, to British and U.S. intelligence agencies monitoring activities of their citizens. They seem new largely because, traditionally, intelligence agencies on both sides of the Atlantic were excessively secretive about their past activities: even the names “GCHQ” and “NSA” were airbrushed from declassified records, and thus missing from major historical works and scholarship on on post-war international relations. The resulting secrecy about British and U.S. intelligence has led to misunderstandings and conspiracy theories in societies about them. Newly opened secret records now reveal the long history of many subjects seen in today’s news-cycle: Anglo-American intelligence cooperation, interference by countries in foreign elections, disinformation, and the use and abuse of intelligence by governments. Newly declassified records also add to our understanding of major chapters of international history, like Britain’s post-war end of empire. Without overcoming our historical amnesia disorder about U.S. and British intelligence, citizens, scholars and policy-makers cannot hope to understand the proper context for what secret agencies are doing today
Learning Dramatically with Linfield Theatre
Calder Ifft discusses student engagement at Linfield College with regard to learning outside the classroom through participation in the Linfield Theatre program.https://digitalcommons.linfield.edu/inauguration2019_students/1012/thumbnail.jp
What use are formal design and analysis methods to telecommunications services?
Have formal methods failed, or will they fail, to help us solve problems of detecting and resolving of feature interactions in telecommunications software? This paper contains SWOT(Strengths, Weaknesses, Opportunities and Threats) analysis of the use of formula design and analysis methods in feature interaction analysis and makes some suggestions for future research
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