Eric C. R. Hehner, called Rick, is a Canadian

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

 computer scientist

Computer scientist

A computer scientist is a scientist who has acquired knowledge of computer science, the study of the theoretical foundations of information and computation and their application in computer systems....

.

Eric Hehner was born on 16 September 1947 in Ottawa

Ottawa

Ottawa is the capital of Canada, the second largest city in the Province of Ontario, and the fourth largest city in the country. The city is located on the south bank of the Ottawa River in the eastern portion of Southern Ontario...

. He studied mathematics

Mathematics

Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

 and physics

Physics

Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...

 at Carleton University

Carleton University

Carleton University is a comprehensive university located in the capital of Canada, Ottawa, Ontario. The enabling legislation is The Carleton University Act, 1952, S.O. 1952. Founded as a small college in 1942, Carleton now offers over 65 programs in a diverse range of disciplines. Carleton has...

, obtaining his first degree in 1969. He gained a PhD

PHD

PHD may refer to:*Ph.D., a doctorate of philosophy*Ph.D. , a 1980s British group*PHD finger, a protein sequence*PHD Mountain Software, an outdoor clothing and equipment company*PhD Docbook renderer, an XML renderer...

 in computer science

Computer science

Computer science or computing science is the study of the theoretical foundations of information and computation and of practical techniques for their implementation and application in computer systems...

 from the University of Toronto

University of Toronto

The University of Toronto is a public research university in Toronto, Ontario, Canada, situated on the grounds that surround Queen's Park. It was founded by royal charter in 1827 as King's College, the first institution of higher learning in Upper Canada...

 in 1974. He then joined the faculty there, becoming a full professor in 1983. He became the Bell University Chair in Software Engineering

Software engineering

Software Engineering is the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software, and the study of these approaches; that is, the application of engineering to software...

 in 2001.

Hehner's main research area is formal methods

Formal methods

In computer science and software engineering, formal methods are a particular kind of mathematically-based techniques for the specification, development and verification of software and hardware systems...

, particularly for programming. In 1979, Hehner invented a method of representing rational numbers with current University of Victoria

University of Victoria

The University of Victoria, often referred to as UVic, is the second oldest public research university in British Columbia, Canada. It is a research intensive university located in Saanich and Oak Bay, about northeast of downtown Victoria. The University's annual enrollment is about 20,000 students...

 professor Nigel Horspool

Nigel Horspool

R. Nigel Horspool is a professor of computer science at the University of Victoria. He invented the Boyer–Moore–Horspool algorithm, a fast string search algorithm adapted from the Boyer–Moore string search algorithm...

 called quote notation

Quote notation

Quote notation is a representation of rational numbers for which the addition, subtraction, and multiplication algorithms are the same as for natural numbers, and division is easier than the usual division algorithm, and works in the same right-to-left direction as the other arithmetic algorithms....

, which allows for easier arithmetic and produces no roundoff error in arithmetic calculations implementing a generalization of radix

Radix

In mathematical numeral systems, the base or radix for the simplest case is the number of unique digits, including zero, that a positional numeral system uses to represent numbers. For example, for the decimal system the radix is ten, because it uses the ten digits from 0 through 9.In any numeral...

 notation. Hehner has also influenced many other computer science researchers with his ideas, including Tony Hoare, especially with his concept of predicative programming

Predicative programming

Predicative programming is a methodology for program specification and refinement. The central idea of predicative programming is that each specification is a predicate that is true of acceptable behaviours and false of unacceptable behaviours...

.

External links

• Home page
• DBLP publications
• A Practical Theory of Programming, Professor Hehner's book, freely available in PDF