The 3𝑥+1 Problem as a String Rewriting System

The 3𝑥+1 problem can be viewed, starting with the binary form for any 𝑛∈𝐍, as a string of “runs” of 1s and 0s, using methodology introduced by Błażewicz and Pettorossi in 1983. A simple system of two unary operators rewrites the length of each run, so that each new string represents the next odd int...

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Bibliographic Details
Main Author: Joseph Sinyor
Format: Article
Language:English
Published: Wiley 2010-01-01
Series:International Journal of Mathematics and Mathematical Sciences
Online Access:http://dx.doi.org/10.1155/2010/458563
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Summary:The 3𝑥+1 problem can be viewed, starting with the binary form for any 𝑛∈𝐍, as a string of “runs” of 1s and 0s, using methodology introduced by Błażewicz and Pettorossi in 1983. A simple system of two unary operators rewrites the length of each run, so that each new string represents the next odd integer on the 3𝑥+1 path. This approach enables the conjecture to be recast as two assertions. (I) Every odd 𝑛∈𝐍 lies on a distinct 3𝑥+1 trajectory between two Mersenne numbers (2𝑘−1) or their equivalents, in the sense that every integer of the form (4𝑚+1) with 𝑚 being odd is equivalent to 𝑚 because both yield the same successor. (II) If 𝑇𝑟(2𝑘−1)→(2𝑙−1) for any 𝑟,𝑘,𝑙>0, 𝑙<𝑘; that is, the 3𝑥+1 function expressed as a map of 𝑘's is monotonically decreasing, thereby ensuring that the function terminates for every integer.
ISSN:0161-1712
1687-0425