Floating point numbers don't represent all possible values, just a subset of values representable by a number of bits used. Therefore, in some cases it's reason

Floating point numbers don't represent all possible values, just a subset of values representable by a number of bits used. Therefore, in some cases it's reasonable to treat floating point numbers not as "exact point on a number scale", but rather a range between a number and the next possible representable number. In the case of +0.0 and -0.0, they can be treated as values between zero and the smallest representable number (about 5.4E-079 for 32 bit floats). It isn't a very common use case since dealing with such small numbers isn't a very common thing, but it is definitely a possibility.