A Hodge-Tate weight of a -adic representation
of the absolute Galois
group of a finite extension
is an integer appearing in
its Hodge-Tate decomposition after extension to the completed algebraic
closure
.
For a finite-dimensional
representation, the convention here writes that decomposition
as
The weights are the integers with multiplicities
. The representation is Hodge-Tate when such a finite
decomposition exists, and
has cyclotomic action of exponent
. Thus the cyclotomic representation
has weight
in this convention. Some authors use the opposite sign.
The regularity condition in the two-dimensional Fontaine-Mazur modularity assertion requires distinct Hodge-Tate weights.