  This paper is devoted to the study and the obtaining of the general relation
between the real part and the imaginary part of the magnetic susceptibility
function in the Laplace domain.
  This new theoretical technique is general, and can be applied to any magnetic
material, that can be considered like causal and Linear time invariant (LTI).
  A discussion of the causality which is extensively used in Physics has been
done. To obtain the relations, some important concepts like Titchmarsh's
theorem and Cauchy's Theorem have been reviewed, which results in the integral
of a analytic function, that is formed with the magnetic susceptibility used in
the Laplace domain.
  The Cauchy Integral expression in the Laplace domain under certain conditions
leads to a general relations between real and imaginary part of the magnetic
susceptibility in the complex \textit{s}-plane. These new relationships allow
the validation of the magnetic susceptibilility functions developed by
different researchers, in the Laplace domain, not just the frequency response
like the well known Kramers-Kronig relations. Under certain conditions in these
new general relations, the well known K-K relations can be obtained as a
particular case.
