fix issue #188
the beginner transformation split_vc
is now using introduce_premises
followed by subst_all
, instead of simplify_trivial_quantification
followed by introduce_premises
.
following Andrei's suggestion, instead of subst_all
we instead substitute
only the symbols that (1) were introduced earlier and (2) do not have
any attributes [@model...]
so as to keep symbols present in the initial
code.