Dirac bracket and Nambu structures

Abstract: A relation between the Dirac bracket (DB) and Nambu bracket (NB) is presented. The Nambu bracket can be related with Dirac bracket if we can write the DB as a generalized Poisson structure. The NB associated with DB have all the standard properties of the original DB. When the dimension of the phase space is $s+2$ where $s$ is the number of second class constraints, the associated Nambu structure has $s+2$ entries and reduces to the Dirac bracket when $s$ of its entries are fixed to be the second class constraints. In general, when the dimension of phase space is $d=r+s$ a new Nambu structure that describes correctly the constrained dynamics can also be constructed but in thsi case addicional conditidionts are requiered. In that case the associated NB corresponds to a ``Dirac-Nambu'' bracket with $r$ entries.