Lattices are very applicable to several areas of computer science. One of my favorite results involving lattices is the Knaster–Tarski theorem[0], which can be

Lattices are very applicable to several areas of computer science. One of my favorite results involving lattices is the Knaster–Tarski theorem[0], which can be applied to areas ranging from grammars (e.g. showing the existence of a set containing all the strings generated by a BNF grammar) to semantics of programming languages (e.g. giving semantics of looping programs as a least fixed point). Domain theory[1] also makes heavy use of this. [0] https://en.wikipedia.org/wiki/Knaster%E2%80%93Tarski_theorem https://en.wikipedia.org/wiki/Knaster%E2%80%93Tarski_theorem [1] https://en.wikipedia.org/wiki/Domain_theory https://en.wikipedia.org/wiki/Domain_theory