How can I calculate the Euler-Lagrange equation from the Lagrangian density from Gauged Baby Skyrme model in maple using the physics package? Here, the rules of the operation in the inner space are the same that of the vectors conventional: dot and cross products, etc...
Following below the Lagrangian density.

Errata:

How can I to build a Spinor with Physics package? I would like to explore a sigma model  from Lagrangian density. The ideia is search the Euler-Lagrange's equation and energy density of this model.