2 minutes, 13 seconds | The Order of Evaluation - slide 9 : 26 |

Rewrite rules

The *rewrite rules* define semantics preserving transformations of expressions

The goal of applying the rewrite rules is normally to reduce an expression to the simplest
possible form, called a *normal form*.

- Overview of rewrite rules
**Alpha conversion:**rewrites a lambda expression**Beta conversion:**rewrites general function calls- Expresses the idea of substitution, as described by
*the substitution model*

- Expresses the idea of substitution, as described by
**Eta conversion:**rewrites certain lambda expressions to a simpler form