We can’t summarize the contents of Universal Algebra to a few pages. Instead, we are going to pull a few things out of it that we’ve noticed were important enough to show up in other places (places to where we’ve been, so far).
Our Selected Topics list for Universal Algebra includes the following:
Appendix A
An algebra is a set A together with a collection of operations on A to which it has Closure.
An algebra is called a Groupoid if it contains a single binary operation.
Rob Sterling 