reduce: some cases on which we fail
There are case where we fail to recognize equivalent automata on Q, because reduce fails to reduce to the empty automaton.
Try
e = vcsn.Q.expression('([ab]*[bc]* & [bc]*[ab]*)ᵗ')
a1 = e.inductive()
a2 = e.automaton()
or
e = vcsn.Q.expression('(a*&a*a*)ᵗ')
a1 = e.inductive()
a2 = e.automaton()