Mapping wave forms to sphere, does wave form y=0 have a reflection?

Zero does not have an inverse.
And y=0 does not have an inverse.
Does the wave form y=0 for all x have an inverse?

What conditions should an inverse of a 'wave form' fulfil ?


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BvU said:

What conditions should an inverse of a 'wave form' fulfil ?


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My first thought is inverse polarity, but if the inverse wave form comprises -y values, any y=0 wouldn't have an inverse -y, so maybe the inverse wave form would not be strictly continuous? That seems asymmetric with respect to inversion...

edit-- I'm using the wrong term, inversion swaps the range and domain, what I am asking about is reflection about the x axis... y -> -y
This is in the context of antipodean pairs on the sphere

More checking, but it looks like zero does have reflection...