Hi! Nice to be here! I have a theorem from the article:Local and global extrema for functions of several variables:

Theorem:TheoremLet be a cubic in two variables. Suppose has a local minimum at . Then has other critical points.

Proof:Proof:there are no repeated roots in the cubic term, theorem 3 gives the result.Thus we let have double or triple root, and after a linear transformation we have either:

I understand the remainder of the proof...

I have a question for the bold part. How received these two polynomials?? I would ask for launching.

Please reply.

Grettings for all !

Ignis.