Is there a name for this concept?

If T and U are temperaments expressed in Z^n, then consider the
subgroup U(ker T). Is there a name for this concept?

It's really useful when comparing categories from one temperament to
another, as it gives you direct information about how interval
categories in one temperament are "smeared" across another.

If there's no name for it, I dub it the "echo" of T in U.

Examples:
- The echo of 12-EDO in meantone is the subspace spanned by the diesis.
- The echo of meantone in porcupine is the subspace spanned by the
tempered porcupine interval |1 -7>, where |1 0> is the octave and |0
1> is the tempered 10/9.
- The echo of meantone in 12-EDO is the unison.
- The echo of 12-EDO in porcupine is all of porcupine space.

etc. This assumes, pretty loosely, that the way we're mapping from
categories in one temperament to another is in terms of ratios. I'm
not claiming this is the ideal way to model categorical perception,
but it's at least one useful way to do it, especially if people like
comma pumps.

-Mike