answer(empty_sequence, "ab").
answer(concatenation, "c").
answer(alternative, "c").
answer(ite_13, yes).
answer(ite_23, yes).
answer(ite_4, yes).
answer(ite_single, no).
answer(grammar_body_goal, "a").
answer(phrase_nonterminal, "b").
answer(cut_identity, "ab").
answer(negation_identity, "bc").
answer(negation_blocks, no).
answer(terminal_split, b).