1. What is a group?

1.1 A famous toy

See also Rubik’s Cube group.

1.2 Considering the cube

The language in this chapter is alluding to Group action, a concept that we’ll see later in the book.

The “action” language is in fact quite appropriate; if you’re studying group theory with an application to robotics in mind then you can see the possible actions the robot can make in terms of moving limbs as actions in the General linear group.