Title
Two discrete versions of the Inscribed Square Conjecture and some related problems
Abstract
The Inscribed Square Conjecture has been open since 1911. It states that any plane Jordan curve J contains four points on a non-degenerate square. In this article two different discrete versions of this conjecture are introduced and proved. The first version is in the field of digital topology: it is proved that the conjecture holds for digital simple closed 4-curves, and that it is false for 8-curves. The second one is in the topological graph theory field: it is proved that any cycle of the grid Z^2 contains an inscribed square with integer vertices. The proofs are based on a theorem due to Pak. An infinite family of 4-curves in the digital plane containing a single non-degenerate inscribed square is introduced as well as a second infinite family containing one 4-curve with exactly n inscribed squares for each positive integer value of n. Finally an algorithm with time complexity O(n^2) is given to find inscribed squares in simple digital curves.
Year
DOI
Venue
2011
10.1016/j.tcs.2010.10.004
Theor. Comput. Sci.
Keywords
DocType
Volume
Jordan Curve Theorem,non-degenerate square,Inscribed Square Conjecture,infinite family,digital simple,Digital topology,digital plane,Simple closed digital curves,simple digital curve,8-connectivity,digital topology,n inscribed square,discrete version,related problem,single non-degenerate inscribed square,4-connectivity,inscribed square,integer vertex
Journal
412
Issue
ISSN
Citations 
15
Theoretical Computer Science
0
PageRank 
References 
Authors
0.34
2
2
Name
Order
Citations
PageRank
Feliu Sagols141.58
Raúl Marín210.82