UNION-THEORIES.html -- ACL2 Version 6.3

## UNION-THEORIES

union two theories

    Major Section:  THEORIES

    Example:
    (union-theories (current-theory 'lemma3)
                    (theory 'arith-patch))

    General Form:
    (union-theories th1 th2)

where `th1` and `th2` are theories (see theories). To each of the arguments there corresponds a runic theory. This function returns the union of those two runic theories, represented as a list and ordered chronologically.

This ``function'' is actually a macro that expands to a term mentioning the single free variable `world`. When theory expressions are evaluated by `in-theory` or the `:``in-theory` hint, `world` is bound to the current ACL2 world.