Chapter 3

1. You specify what needs to be done algorithmically, with the help of the low-level operations defined in the imperative collections.
2. You specify your program as an expression, with the help of high-level operations defined in the functional collections.
3. All the algorithms you may need are already implemented in the framework. You only need to call them by name when you need them. All the programs you may want to write can be expressed as a combination of the high-level operations implemented in the framework.

4. Understand the program as a mathematical expression rather than an algorithm. An expression is a structure that consists of operands (data) bound together by operators (behavior).
5. Lesser mental load on the programmer's mind. Algebraic programs usually remove side effects such as errors or time from the equation. So you do not need to think about them. This...