03/03/2023, 01:17 PM
the matrix multiplication has issues if you mean carleman and such.
This follows from the many sqrt a matrix can have.
if the eigenvalues are nonreal the n th root of the matrix can have n solutions PER eigenvalue.
So the n th root of a m*m matrix can have up to
n^m
SO
a matrix of size 10 can have
2^10 sqrt roots.
and that does not consider the one-periodic function.
So unless you define a way to get the correct roots ( such as closest to the + reals )
and that works out nice , even with increasing matrix size
then and only then may you have a good definition.
It has been suggested to use
A^(1/n) = exp( 1/n ln(A) )
this way maybe you have the semi group iso , IF the ln and exp do not give issues.
( again by conjugate composition )
But this seems only consistant when locally around a fixpoint :
so basically equivalent to the fixpoint expansion like koenings function ( assuming f ' (fix ) is ok )
regards
tommy1729
This follows from the many sqrt a matrix can have.
if the eigenvalues are nonreal the n th root of the matrix can have n solutions PER eigenvalue.
So the n th root of a m*m matrix can have up to
n^m
SO
a matrix of size 10 can have
2^10 sqrt roots.
and that does not consider the one-periodic function.
So unless you define a way to get the correct roots ( such as closest to the + reals )
and that works out nice , even with increasing matrix size
then and only then may you have a good definition.
It has been suggested to use
A^(1/n) = exp( 1/n ln(A) )
this way maybe you have the semi group iso , IF the ln and exp do not give issues.
( again by conjugate composition )
But this seems only consistant when locally around a fixpoint :
so basically equivalent to the fixpoint expansion like koenings function ( assuming f ' (fix ) is ok )
regards
tommy1729

