3. Denotational Semantics
This method maps a program directly to its meaning called its denotation. The denotation is usually a mathematical value, such as a number or a function.
No interpreters are used, a valuation function maps a program directly to its meaning.
A denotational definition is more abstract than an operational definition, as it does not specify computation steps.
Its high level, modular structure makes it especially useful to language designers and users, as the individual parts of a language can be studied without having to examine the entire definition.