Three Lines In A Circle

One line straight down. One line to the right. One line to the left, then a circle. That was all—just three lines in a circle. This bold picture book tells the story of the peace symbol—designed in 1958 by a London activist protesting nuclear weapons—and how it inspired people all over the world. Depicting the symbol's travels from peace marches and liberation movements to the end of apartheid and the fall of the Berlin Wall, Three Lines in a Circle offers a message of inspiration to today's children and adults who are working to create social change. An author’s note provides historical background and a time line of late twentieth-century peace movements.

Geometry: The Line and the Circle is an undergraduate text with a strong narrative that is written at the appropriate level of rigor for an upper-level survey or axiomatic course in geometry. Starting with Euclid's Elements, the book connects topics in Euclidean and non-Euclidean geometry in an intentional and meaningful way, with historical context. The line and the circle are the principal characters driving the narrative. In every geometry considered—which include spherical, hyperbolic, and taxicab, as well as finite affine and projective geometries—these two objects are analyzed and highlighted. Along the way, the reader contemplates fundamental questions such as: What is a straight line? What does parallel mean? What is distance? What is area? There is a strong focus on axiomatic structures throughout the text. While Euclid is a constant inspiration and the Elements is repeatedly revisited with substantial coverage of Books I, II, III, IV, and VI, non-Euclidean geometries are introduced very early to give the reader perspective on questions of axiomatics. Rounding out the thorough coverage of axiomatics are concluding chapters on transformations and constructibility. The book is compulsively readable with great attention paid to the historical narrative and hundreds of attractive problems.

Circles and spheres are central objects in geometry. This work looks at systems of circles and spheres and the geometry and groups associated to them. It also examines the differential and projective geometry of the space of various spheres in a given space.