and 0, whatever
may be, the function will assume the value 1 for certain arguments, but will never assume any greater value. Hence the ultimate section consists of all real numbers, positive and negative, up to and including 1; i.e. it consists of all negative numbers together with 0, together with the positive numbers up to and including 1.
Similarly the "ultimate upper section" consists of all positive numbers together with 0, together with the negative numbers down to and including -1.
Thus the "ultimate oscillation" consists of all real numbers from -1 to 1, both included.
We may say generally that the "ultimate oscillation" of a function as the argument approaches
from below consists of all those numbers
