Degree 2 bubble on a interval

• \(R\) is the reference interval. The following numbering of the subentities of the reference is used:

• \(\mathcal{V}\) is spanned by: \(x \left(1 - x\right)\)
• \(\mathcal{L}=\{l_0,...,l_{0}\}\)
• Functionals and basis functions:

\(\displaystyle l_{0}:v\mapsto v(\tfrac{1}{2})\)

\(\displaystyle \phi_{0} = 4 x \left(1 - x\right)\)

This DOF is associated with edge 0 of the reference element.