Two algorithms in search of a type system
Abstract
The authors' ATR programming formalism is a version of call-by-value PCF under a complexity-theoretically motivated type system. ATR programs run in type-2 polynomial-time and all standard type-2 basic feasible functionals are ATR-definable (ATR types are confined to levels 0, 1, and 2). A limitation of the original version of ATR is that the only directly expressible recursions are tail-recursions. Here we extend ATR so that a broad range of affine recursions are directly expressible. In particular, the revised ATR can fairly naturally express the classic insertion- and selection-sort algorithms, thus overcoming a sticking point of most prior implicit-complexity-based formalisms. The paper's main work is in refining the original time-complexity semantics for ATR to show that these new recursion schemes do not lead out of the realm of feasibility.
Keywords
Cite
@article{arxiv.0710.0824,
title = {Two algorithms in search of a type system},
author = {Norman Danner and James S. Royer},
journal= {arXiv preprint arXiv:0710.0824},
year = {2008}
}
Comments
30 pages. Final version to appear in Theory of Computing Systems