is mentioned by

Def rel_arg_typ(rn;i;de) == Case(rn) Case eq(Q) = > Q Case R = > (de.rel(R))[i] Default = > False	[rel_arg_typ]
Def tc1(r;de) == Case(r.name) Case eq(Q) = > ||r.args|| = 2 Case R = > ||de.rel(R)|| = ||r.args|| Default = > False	[tc1]

Try larger context: GenAutomata