On the Square Peg Problem and its relatives

Toeplitz's Square Peg Problem asks whether every continuous simple closed curve in the plane contains the four vertices of a square. It has been proved for various classes of sufficiently smooth curves, some of which are dense, none of which are open. In this paper we prove it for several open classes of curves, one of which is also dense. This can be interpreted in saying that the Square Peg Problem is solved for generic curves. The latter class contains all previously known classes for which the Square Peg Problem has been proved in the affirmative. [footnote] We also prove results about rectangles inscribed in immersed curves. Finally, we show that the problem of finding a regular octahedron on metric 2-spheres has a "topological counter-example", that is, a certain test map with boundary condition exists

The algebraic square peg problem

The square peg problem asks whether every continuous curve in the plane that starts and ends at the same point without self-intersecting contains four distinct corners of some square. Toeplitz conjectured in 1911 that this is indeed the case. Hundred years later we only have partial results for curves with additional smoothness properties. The contribution of this thesis is an algebraic variant of the square peg problem. By casting the set of squares inscribed on an algebraic plane curve as a variety and applying Bernshtein's Theorem we are able to count the number of such squares. An algebraic plane curve defined by a polynomial of degree m inscribes either an infinite amount of squares, or at most (m4 - 5m2 + 4m)= 4 squares. Computations using computer algebra software lend evidence to the claim that this upper bound is sharp for generic curves. Earlier work on Toeplitz's conjecture has shown that generically an odd number of squares is inscribed on a smooth enough Jordan curve. Examples of real cubics and quartics suggest that there is a similar parity condition on the number of squares inscribed on some topological types of algebraic plane curves that are not Jordan curves. Thus we are led to conjecture that algebraic plane curves homeomorphic to the real line inscribe an even number of squares

Analyzing State Attempts at Implementing the Common Core State Standards for High School Geometry: Case Studies of Utah and New York

This study analyzes two state attempts at aligning curricula to the Common Core State Standards (CCSS) in secondary school geometry. The education departments of Utah and New York have approved curricula aimed at aligning to the Common Core State Standards: the Mathematics Vision Project (MVP) and EngageNY (ENY) respectively. This study measures the extent to which those curricula align with the content demands of the relevant Common Core Standards. The results indicate that, while the two curricula vary in structure and assumptions about learners, each one aligns well with the Common Core State Standards in secondary school geometry. We conclude with recommendations for individuals and entities concerned with aligning geometry curricula to the Common Core State Standards

Square Peg Problem in 2-Dimensional Lattice

The Square Peg Problem, also known as the inscribed square problem poses a question: Does every simple closed curve contain all four points of a square? This project introduces a new approach in proving the square peg problem in 2-dimensional lattice. To accomplish the result, this research first defines the simple closed curve on 2-dimensional lattice. Then we identify the existence of inscribed half-squares, which are the set of three points of a square, in a lattice simple closed curve. Then we finally add a last point to form a half-square into a square to examine whether all four points of a square exist in a lattice simple closed curve. A sage program was used to find all missing corners of all inscribed half-squares. This has enabled us to look at the pattern of sets of all missing corners in specific shapes like rectangles. By the end, we were able to conjecture that there exist missing corners in the interior and the exterior of the lattice simple closed curve unless the shape is a square. It is obvious that the square has an inscribed square. Hence if we could prove that the set of all missing corners is connected, we could give a new proof of the square peg problem in 2-dimensional lattice