[printers] Support lt and gt as relational operators for Marabou.

src/printers/marabou.ml

@@ -76,10 +76,14 @@ let rec print_term info fmt t =
     with
     | Some s1, Some s2 ->
       if Term.ls_equal ls info.ls_rel_float.le
+         || Term.ls_equal ls info.ls_rel_float.lt
          || Term.ls_equal ls info.ls_rel_real.le
+         || Term.ls_equal ls info.ls_rel_real.lt
       then Fmt.pf fmt "+%s -%s <= 0" s1 s2
       else if Term.ls_equal ls info.ls_rel_float.ge
+              || Term.ls_equal ls info.ls_rel_float.gt
               || Term.ls_equal ls info.ls_rel_real.ge
+              || Term.ls_equal ls info.ls_rel_real.gt
       then Fmt.pf fmt "+%s -%s >= 0" s1 s2
       else Printer.unsupportedTerm t "Marabou: unknown relational operator"
     | _ -> Printer.unsupportedTerm t "Marabou: unknown variable(s)")