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ICFP 2018
Sun 23 - Sat 29 September 2018 St. Louis, Missouri, United States
Wed 26 Sep 2018 10:52 - 11:15 at Stifel Theatre - Semantics Chair(s): Sam Lindley

Bulk types such as sets, bags, and lists are monads, and therefore support a notation for database queries based on comprehensions. This fact is the basis of much work on database query languages. The monadic structure easily explains most of standard relational algebra—specifically, selections and projections—allowing for an elegant mathematical foundation for those aspects of database query language design. Most, but not all: monads do not immediately offer an explanation of relational join or grouping, and hence important foundations for those crucial aspects of relational algebra are missing. The best they can offer is cartesian product followed by selection. Adjunctions come to the rescue: like any monad, bulk types also arise from certain adjunctions; we show that by paying due attention to other important adjunctions, we can elegantly explain the rest of standard relational algebra. In particular, this leads directly to an efficient implementation, even of joins.

Wed 26 Sep
Times are displayed in time zone: Guadalajara, Mexico City, Monterrey change

10:30 - 12:00
SemanticsResearch Papers at Stifel Theatre
Chair(s): Sam LindleyUniversity of Edinburgh, UK
10:30
22m
Talk
Partially-Static Data as Free Extension of Algebras
Research Papers
Jeremy YallopUniversity of Cambridge, UK, Tamara von GlehnUniversity of Cambridge, Ohad KammarUniversity of Oxford
Link to publication DOI Pre-print
10:52
22m
Talk
Relational Algebra by Way of AdjunctionsDistinguished Paper
Research Papers
Jeremy GibbonsDepartment of Computer Science, University of Oxford, Fritz HengleinDepartment of Computer Science, University of Copenhagen (DIKU), Ralf HinzeRadboud University Nijmegen, Nicolas WuUniversity of Bristol, UK
DOI
11:15
22m
Talk
Strict and Lazy Semantics for Effects: Layering Monads and Comonads
Research Papers
Andrew HirschCornell University, Ross TateCornell University
DOI
11:37
22m
Talk
What's the Difference? A Functional Pearl on Subtracting Bijections
Research Papers
Brent YorgeyHendrix College, Kenneth Foner
DOI