Proportionally modular diophantine inequalities and the Stern-Brocot tree

Authors:
M. Bullejos and J. C. Rosales

Journal:
Math. Comp. **78** (2009), 1211-1226

MSC (2000):
Primary 11D75, 20M14

Published electronically:
August 12, 2008

MathSciNet review:
2476582

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Abstract | References | Similar Articles | Additional Information

Abstract: Given positive integers and to compute a generating system for the numerical semigroup whose elements are all positive integer solutions of the inequality is equivalent to computing a Bézout sequence connecting two reduced fractions. We prove that a proper Bézout sequence is completely determined by its ends and we give an algorithm to compute the unique proper Bézout sequence connecting two reduced fractions. We also relate Bézout sequences with paths in the Stern-Brocot tree and use this tree to compute the minimal positive integer solution of the above inequality.

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Additional Information

**M. Bullejos**

Affiliation:
Departamento de Álgebra, Universidad de Granada, 18071 Granada, Spain

Email:
bullejos@ugr.es

**J. C. Rosales**

Affiliation:
Departamento de Álgebra, Universidad de Granada, 18071 Granada, Spain

Email:
jrosales@ugr.es

DOI:
https://doi.org/10.1090/S0025-5718-08-02173-X

Keywords:
Diophantine inequation,
numerical semigroup,
Stern-Brocot tree

Received by editor(s):
January 3, 2008

Received by editor(s) in revised form:
April 4, 2008

Published electronically:
August 12, 2008

Additional Notes:
This work was partially supported by research projects MTM2005-03227 and MTM2007-62346

Article copyright:
© Copyright 2008
American Mathematical Society