Decomposition theorem: uniqueness of block sizes Prove that the number $s$ and the sizes of the blocks $r_1, \ldots, r_s$ that appear in question $9^\circ$ depend only on $u$ and not on the choice of basis. You may use question $2^\circ$.
\textbf{Decomposition theorem: uniqueness of block sizes}\\
Prove that the number $s$ and the sizes of the blocks $r_1, \ldots, r_s$ that appear in question $9^\circ$ depend only on $u$ and not on the choice of basis. You may use question $2^\circ$.