Hello!
I’m trying to solve a problem in which appear derivatives of fourth order and in order to avoid that, I’ve been introduced an auxiliary variable so that, instead of solving one variational problem but two. Here I provide the relevant equations:
As you can see, the first problem is related to the R_i vector while the second is related to the u_i vector.
So far I’ve been doing well with declaring the functions and tensor quantities, but my question is this: It’s OK If I use the same space for the R_i and u_i equations?