Bubble enriched Lagrange

\(\mathcal{P}_k=\operatorname{span}\left\{\prod_{i=1}^dx_i^{p_i}\middle|\sum_{i=1}^dp_i\leqslant k\right\}\)

\(\mathcal{Z}^{(11)}_k=\left\{p\in \mathcal{P}_{k}\middle|p=0\text{ on the boundary}\right\}\)

Before trying this example, you must install Symfem:

pip3 install symfem

This element can then be created with the following lines of Python:

import symfem

# Create bubble enriched Lagrange order 1 on a triangle
element = symfem.create_element("triangle", "bubble enriched Lagrange", 1)

# Create bubble enriched Lagrange order 2 on a triangle
element = symfem.create_element("triangle", "bubble enriched Lagrange", 2)