Fritz Henglein Speaks at Loyola

Speaker

Fritz Henglein
Department of Computer Science, University of Copenhagen (DIKU)

Title

What is a Sort Function?

Abstract

Sorting is one of the most-studied subjects of computer science. So it seems silly to ask what a sort function is. Obviously a sort function is a function that permutes sequences such that the elements are in order. This, however, begs the next question: What does it mean to be "in order"? In studying these questions, we will see that comparisons, comparators and sort functions are conceptually and behaviorally interchangeable. From a performance point of view, there is a diff erence, however, depending on which one we implement "natively": Sort functions admit construction of generic distributive sorting algorithms that are not subject to the comparison-based sorting bottleneck.

Bio Sketch

Fritz Henglein's research interests are in semantic, logical and algorithmic aspects of programming languages, specifically type inference, type-based program analysis, algorithmic functional programming and domain-specific languages, and the application of programming language technology, which is presently in enterprise systems (3gERP.org) and health care processes (trustcare.eu).

After undergraduate studies at Technische Universität München, he obtained his Ph.D. from Rutgers University and joined New York University, IBM Research, Utrecht University and the Department of Computer Science at the University of Copenhagen (DIKU, diku.dk). After co-starting a company to keep the Y2K bug at bay (Hafnium ApS, hafnium.com) and a university (the IT University of Copenhagen, itu.dk/) to increase IT proficiency, he rejoined DIKU as professor with special duties in programming languages. He is now head of the programming languages and algorithms group at DIKU. His goal is to contribute to the development of software that comes with technical and legal guarantees of having no defects (which should be considered a very modest ambition indeed).