static L<TripleWeb> ai_triples_multi(Collection<Symbol> a, Collection<Symbol> b, Collection<Symbol> c, AbstractThoughtSpace ts) {
  new LinkedHashSet<TripleWeb> l;
  if (!empty(a) && !empty(b) && !empty(c))
    for (Symbol _a : a)
      for (Symbol _b : b)
        for (Symbol _c : c)
          l.addAll(ai_triples(_a, _b, _c, ts));
  ret cloneList(l);
}

static L<TripleWeb> ai_triples_multi(Symbol a, Collection<Symbol> b, Symbol c, AbstractThoughtSpace ts) {
  ret ai_triples_multi(ll(a), b, ll(c), ts);
}

static L<TripleWeb> ai_triples_multi(Collection<Symbol> a, Collection<Symbol> b, Symbol c, AbstractThoughtSpace ts) {
  ret ai_triples_multi(a, b, ll(c), ts);
}

static L<TripleWeb> ai_triples_multi(Collection<Symbol> a, Symbol b, Symbol c, AbstractThoughtSpace ts) {
  ret ai_triples_multi(a, ll(b), ll(c), ts);
}

static L<TripleWeb> ai_triples_multi(Symbol a, Symbol b, Collection<Symbol> c, AbstractThoughtSpace ts) {
  ret ai_triples_multi(ll(a), ll(b), c, ts);
}