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- Todd J. Green, Gregory Karvounarakis, Val Tannen
- PODS
- 2007

We show that relational algebra calculations for incomplete databases, probabilistic databases, bag semantics and why-provenance are particular cases of the same general algorithms involving semirings. This further suggests a comprehensive provenance representation that uses semirings of polynomials. We extend these considerations to datalog and semirings… (More)

- Val Tannen, Thierry Coquand, Carl A. Gunter, Andre Scedrov
- Inf. Comput.
- 1991

We present a method for providing semantic interpretations for languages with a type system featuring inheritance polymorphism. Our approach is illustrated on an extension of the language Fun of Cardelli and Wegner, which we interpret via a translation into an extended polymorphic lambda calculus. Our goal is to interpret inheritances in Fun via coercion… (More)

We consider systems for data sharing among heterogeneous peers related by a network of schema mappings. Each peer has a locally controlled and edited database instance, but wants to ask queries over related data from other peers as well. To achieve this, every peer's updates propagate along the mappings to the other peers. However, this update exchange is… (More)

- Val Tannen, Peter Buneman, Limsoon Wong
- ICDT
- 1992

We investigate the properties of a simple programming language whose main computational engine is structural recursion on sets. We describe a progression of sublanguages in this paradigm that (1) have increasing expressive power, and (2) illustrate robust conceptual restrictions thus exhibiting interesting additional properties. These properties suggest… (More)

- Peter Buneman, Shamim A. Naqvi, Val Tannen, Limsoon Wong
- Theor. Comput. Sci.
- 1995

We present a new principle for the development of database query languages that the primitive operations should be organized around types. Viewing a relational database as consisting of sets of records, this principle dictates that we should investigate separately operations for records and sets. There are two immediate advantages of this approach, which is… (More)

- Stephen A. Goff, Matthew Vaughn, +62 authors Dan Stanzione
- Front. Plant Sci.
- 2011

The iPlant Collaborative (iPlant) is a United States National Science Foundation (NSF) funded project that aims to create an innovative, comprehensive, and foundational cyberinfrastructure in support of plant biology research (PSCIC, 2006). iPlant is developing cyberinfrastructure that uniquely enables scientists throughout the diverse fields that comprise… (More)

- Todd J. Green, Val Tannen
- IEEE Data Eng. Bull.
- 2006

This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of the University of Pennsylvania's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for… (More)

- Val Tannen, Jean H. Gallier
- Theor. Comput. Sci.
- 1991

We study combinations of many-sorted algebraic term rewriting systems and polymorphic lambda term rewriting. Algebraic and lambda terms are mixed by adding the symbols of the algebraic signature to the polymorphic lambda calculus, as higher-order constants. We show that if a many-sorted algebraic rewrite system R is strongly normalizing (terminating,… (More)

- Alin Deutsch, Val Tannen
- ICDT
- 2003

We state and solve the query reformulation problem for XML publishing in a general setting that allows mixed (XML and relational) storage for the proprietary data and exploits redundancies (materialized views, indexes and caches) to enhance performance. The correspondence between published and proprietary schemas is specified by views in both directions,… (More)

- Val Tannen
- [1988] Proceedings. Third Annual Information…
- 1988

The author studies the higher-order rewrite/equational proof systems obtained by adding the simply typed lambda calculus to algebraic rewrite/equational proof systems. He shows that if a many-sorted algebraic rewrite system has the Church-Rosser property, then the corresponding higher-order rewrite system which adds simply typed beta -reduction has the… (More)