Finite element degree of freedom (${\ell }_i\in P^{\ast }$)

A finite element degree of freedom is one of the linear functionals chosen to specify a local shape function in a finite-dimensional vector space $P$. Examples are point evaluation functionals and edge or cell integrals. The finite element is an unisolvent finite element when the complete list gives a bijection from $P$ to the corresponding list of real values.