you have by ?
This is bijective because
I think you can check it is a morphism.
a belongs to R
show that the map
L: R^n------R^n>0
(R^n>0 denote the n-fold cartesian product of R>0 with itself)
(a1)
(....) ----------
(an)
(e^a1)
(.....)
(e^an)
is a isomorphism between the vector space R^n and the vector space R^n>0