Lemmas about arithmetic operations and intervals. #
inv_mem_Ixx_iff
, sub_mem_Ixx_iff
add_mem_Ixx_iff_left
add_mem_Ixx_iff_right
sub_mem_Ixx_iff_left
sub_mem_Ixx_iff_right
inv_mem_Ixx_iff
, sub_mem_Ixx_iff
add_mem_Ixx_iff_left
add_mem_Ixx_iff_right
sub_mem_Ixx_iff_left
sub_mem_Ixx_iff_right