In 1979, Hehner invented a method of representing rational numbers with current University of Victoria professor Nigel Horspool called quote notation, which allows for easier arithmetic and produces no roundoff error in arithmetic calculations implementing a generalization of radix notation.
Radix sort dates back as far as 1887 to the work of Herman Hollerith on tabulating machines.
A Gray code for numbers in a given radix is a sequence that contains each number up to a given limit exactly once, in such a way that each pair of consecutive numbers differs by one in a single digit.