A previous note gives a rule for determining the sequence of + and - signs to obtain the ith largest value of +ƒ(±ƒ(±ƒ(··· ±ƒ(x)···))) when ƒ(x) is positive and monotonic [1, p. 46, §2]. Shortly after publication the writer received a letter dated March 9, 1972, from John Murchland, of the Planning & Transport Research & Computation Co. Ltd., London, in which he mentioned that the conversion scheme for obtaining the ± sign sequence from i - 1 happens to be also the standard way of going from a binary number to its Gray code equivalent, when after the conversion every plus sign is replaced by 0 and every minus sign by 1.
The full text of this article is premium content
No entries found
Log in to Read the Full Article
Please select one of the options below for access to premium content and features.
Create a Web Account
If you are already an ACM member, Communications subscriber, or Digital Library subscriber, please set up a web account to access premium content on this site.
Join the ACM
Become a member to take full advantage of ACM's outstanding computing information resources, networking opportunities, and other benefits.
Subscribe to Communications of the ACM Magazine
Get full access to 50+ years of CACM content and receive the print version of the magazine monthly.
Purchase the Article
Non-members can purchase this article or a copy of the magazine in which it appears.