"cic:/matita/arithmetics/nat/lt_plus_to_minus.con"
"cic:/matita/arithmetics/nat/lt_plus_to_minus_r.con"
"cic:/matita/arithmetics/nat/lt_inv_plus_l.con"
"cic:/matita/arithmetics/nat/lt_plus_to_minus.con"
"cic:/matita/arithmetics/nat/lt_plus_to_minus_r.con"
"cic:/matita/arithmetics/nat/lt_inv_plus_l.con"