Added primitive recursive functions (Norbert Voelker's code) to the datatype
package.
HOL: Higher-Order Logic
This directory contains the Standard ML sources of the Isabelle system for
Higher-Order Logic. Important files include
ROOT.ML -- loads all source files. Enter an ML image containing Pure
Isabelle and type: use "ROOT.ML";
Makefile -- compiles the files under Poly/ML or SML of New Jersey
ex -- subdirectory containing examples. To execute them, enter an ML image
containing HOL and type: use "ex/ROOT.ML";
Subst -- subdirectory defining a theory of substitution and unification.
Useful references on Higher-Order Logic:
P. B. Andrews,
An Introduction to Mathematical Logic and Type Theory
(Academic Press, 1986).
J. Lambek and P. J. Scott,
Introduction to Higher Order Categorical Logic (CUP, 1986)