Materials were written for an entire year's course in geometry in which transformations were used to develop the concepts of congruence, similarity, and symmetry, as well as being a vehicle for proof.

About twenty years ago, Olgur Celikbas attended a conference on algebra in Turkey. He and his then girlfriend, Ela Özçağlar, had recently graduated from college in Ankara; both had studied math. At ...

Symplectic geometry is a relatively new field with implications for much of modern mathematics. Here’s what it’s all about. In the early 1800s, William Rowan Hamilton discovered a new kind of ...