Unsolved problem about inscribing a square in a Jordan curve
Unsolved problem in mathematics
Does every
Jordan curve have an inscribed square?
Example: The black dashed curve goes through all corners of several blue squares.
The inscribed square problem , also known as the square peg problem or the Toeplitz conjecture , is an unsolved question in geometry : Does every plane simple closed curve contain all four vertices of some square ? This is true if the curve is convex or piecewise smooth and in other special cases. The problem was proposed by Otto Toeplitz in 1911.[ 1] Some early positive results were obtained by Arnold Emch [ 2] and Lev Schnirelmann .[ 3] The general case remains open.[ 4]
^ Toeplitz, O. (1911), "Über einige Aufgaben der Analysis situs", Verhandlungen der Schweizerischen Naturforschenden Gesellschaft (in German), 94 : 197
^ Emch, Arnold (1916), "On some properties of the medians of closed continuous curves formed by analytic arcs", American Journal of Mathematics , 38 (1): 6– 18, doi :10.2307/2370541 , JSTOR 2370541 , MR 1506274
^ Šnirel'man, L. G. (1944), "On certain geometrical properties of closed curves", Akademiya Nauk SSSR I Moskovskoe Matematicheskoe Obshchestvo. Uspekhi Matematicheskikh Nauk , 10 : 34– 44, MR 0012531
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