I'm working in the text "Introduction to Applied Nonlinear Dynamical Systems and Chaos"and I have a doubt in the following exercise
Consider a third-order autonomous vector field near a fixed point having linear part $$\left(\begin{matrix} 0&-\omega&0\\ \omega&0&0\\ 0&0&0 \end{matrix}\right)$$ find the normal form. (Hint: Lump the two coordinates associated with the block$$\left(\begin{matrix} 0&-\omega\\ \omega&0 \end{matrix}\right)$$ into the single complex coordinate.)
My doubt is what means: Lump the two coordinates associated with the...
Thanks in advance.