There is no such thing as the 'mathematical 4th dimension'. Dimensions don't exist by themselves; dimensions are attributes possessed by spaces, and it makes no sense to talk about a 'mathematical 4th dimension' without reference to which space it is a dimension of. In this case, it doesn't matter how many dimensions the space has, so long as it has at least four. And "translating a cube" won't give you a hypercube -- IIRC, translation is merely a change of position.
Talking about a "mathematical 4th dimension" is redudant and confusing -- there is no other sense of dimension that could apply in this context than the mathematical one. And the set definition given for a tesseract might give the mistaken conclusion that all tesseracts have that definition, when only one particular tesseract does. -- SJK