Logic for Computable Functions

Logic for Computable Functions (LCF) is an interactive automated theorem prover developed at the universities of Edinburgh and Stanford by Robin Milner and others in 1972. LCF introduced the general-purpose programming language ML to allow users to write theorem-proving tactics. Theorems in the system are terms of a special "theorem" abstract data type. The ML type system ensures that theorems are derived using only the inference rules given by the operations of the abstract type.

Successors include HOL (Higher Order Logic) and Isabelle.

...
Wikipedia