<HR><PRE><B>Just binary_res_just_by_id(int c1, int n1, int c2, int n2);
</B></PRE>Similar to binary_res_just, except that IDs are given instead of clauses.
<A NAME="clause_level"></A><HR><PRE><B>int clause_level(Topform c);
</B></PRE>Return the level of a clause.  Input clauses have level=0, and
a derived clause has level 1 more than the max of the levels of its parents.
<A NAME="clausify_just"></A><HR><PRE><B>Just clausify_just(Topform tf);
</B></PRE>This routine builds and returns a justification list for