An interactive theorem prover developed at the universities of Edinburgh and Stanford by Robin Milner and others.
LCF introduced the general purpose programming language ML to allow users to write theorem proving tactics.
Theorems in the system are propositions of a special "theorem" abstract datatype.
The ML type system ensures that theorems are derived using only the inference rules given by the operations of the abstract type.
Successors include the
HOL and Isabelle theorem provers.