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Degree 2 serendipity on a quadrilateral
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- \(R\) is the reference quadrilateral. The following numbering of the subentities of the reference is used:
- \(\mathcal{V}\) is spanned by: \(1\), \(x\), \(x^{2}\), \(y\), \(x y\), \(y^{2}\), \(x y^{2}\), \(x^{2} y\)
- \(\mathcal{L}=\{l_0,...,l_{7}\}\)
- Functionals and basis functions:
\(\displaystyle l_{0}:v\mapsto v(0,0)\)
\(\displaystyle \phi_{0} = - 3 x^{2} y + 3 x^{2} - 3 x y^{2} + 7 x y - 4 x + 3 y^{2} - 4 y + 1\)
This DOF is associated with vertex 0 of the reference element.
\(\displaystyle \phi_{0} = - 3 x^{2} y + 3 x^{2} - 3 x y^{2} + 7 x y - 4 x + 3 y^{2} - 4 y + 1\)
This DOF is associated with vertex 0 of the reference element.
\(\displaystyle l_{1}:v\mapsto v(1,0)\)
\(\displaystyle \phi_{1} = x \left(- 3 x y + 3 x + 3 y^{2} - y - 2\right)\)
This DOF is associated with vertex 1 of the reference element.
\(\displaystyle \phi_{1} = x \left(- 3 x y + 3 x + 3 y^{2} - y - 2\right)\)
This DOF is associated with vertex 1 of the reference element.
\(\displaystyle l_{2}:v\mapsto v(0,1)\)
\(\displaystyle \phi_{2} = y \left(3 x^{2} - 3 x y - x + 3 y - 2\right)\)
This DOF is associated with vertex 2 of the reference element.
\(\displaystyle \phi_{2} = y \left(3 x^{2} - 3 x y - x + 3 y - 2\right)\)
This DOF is associated with vertex 2 of the reference element.
\(\displaystyle l_{3}:v\mapsto v(1,1)\)
\(\displaystyle \phi_{3} = x y \left(3 x + 3 y - 5\right)\)
This DOF is associated with vertex 3 of the reference element.
\(\displaystyle \phi_{3} = x y \left(3 x + 3 y - 5\right)\)
This DOF is associated with vertex 3 of the reference element.
\(\displaystyle l_{4}:v\mapsto\displaystyle\int_{e_{0}}v\)
where \(e_{0}\) is the 0th edge.
\(\displaystyle \phi_{4} = 6 x \left(x y - x - y + 1\right)\)
This DOF is associated with edge 0 of the reference element.
where \(e_{0}\) is the 0th edge.
\(\displaystyle \phi_{4} = 6 x \left(x y - x - y + 1\right)\)
This DOF is associated with edge 0 of the reference element.
\(\displaystyle l_{5}:v\mapsto\displaystyle\int_{e_{1}}v\)
where \(e_{1}\) is the 1st edge.
\(\displaystyle \phi_{5} = 6 y \left(x y - x - y + 1\right)\)
This DOF is associated with edge 1 of the reference element.
where \(e_{1}\) is the 1st edge.
\(\displaystyle \phi_{5} = 6 y \left(x y - x - y + 1\right)\)
This DOF is associated with edge 1 of the reference element.
\(\displaystyle l_{6}:v\mapsto\displaystyle\int_{e_{2}}v\)
where \(e_{2}\) is the 2nd edge.
\(\displaystyle \phi_{6} = 6 x y \left(1 - y\right)\)
This DOF is associated with edge 2 of the reference element.
where \(e_{2}\) is the 2nd edge.
\(\displaystyle \phi_{6} = 6 x y \left(1 - y\right)\)
This DOF is associated with edge 2 of the reference element.
\(\displaystyle l_{7}:v\mapsto\displaystyle\int_{e_{3}}v\)
where \(e_{3}\) is the 3rd edge.
\(\displaystyle \phi_{7} = 6 x y \left(1 - x\right)\)
This DOF is associated with edge 3 of the reference element.
where \(e_{3}\) is the 3rd edge.
\(\displaystyle \phi_{7} = 6 x y \left(1 - x\right)\)
This DOF is associated with edge 3 of the reference element.