10,924 research outputs found
Oral History Interview: Warren Brown
This interview is one of a series conducted concerning West Virginia business history. Warren Brown was an employee of BML Lighting, a theatrical lighting company. He discusses: company history; business practices; different jobs they were hired for; their education; bookkeeping; and how technology has affected their business.https://mds.marshall.edu/oral_history/1287/thumbnail.jp
Towards a directed homotopy type theory
In this paper, we present a directed homotopy type theory for reasoning
synthetically about (higher) categories, directed homotopy theory, and its
applications to concurrency. We specify a new `homomorphism' type former for
Martin-L\"of type theory which is roughly analogous to the identity type former
originally introduced by Martin-L\"of. The homomorphism type former is meant to
capture the notions of morphism (from the theory of categories) and directed
path (from directed homotopy theory) just as the identity type former is known
to capture the notions of isomorphism (from the theory of groupoids) and path
(from homotopy theory). Our main result is an interpretation of these
homomorphism types into Cat, the category of small categories. There, the
interpretation of each homomorphism type hom(a,b) is indeed the set of
morphisms between the objects a and b of a category C. We end the paper with an
analysis of the interpretation in Cat with which we argue that our homomorphism
types are indeed the directed version of Martin-L\"of's identity types
Plate tectonics: When ancient continents collide
The geological record preserves scant evidence for early plate tectonics. Analysis of eclogites — metamorphic rocks formed in subduction zones — in the Trans-Hudson mountain belt suggests modern-style subduction may have operated 1,800 million years ago
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