Would someone help me with this problem?

Give an example of a linear operator T on an inner product space V such that N(T) does not equal N(T*).

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- Nov 15th 2007, 08:34 PM #1needhelp_thanksGuest

- Nov 16th 2007, 08:47 AM #2
Is N(T) supposed to be the null space of T, or the dimension of the null space?

If N(T) = null space of T, then you can get an example in two dimensions. Take $\displaystyle T=\begin{bmatrix}0&1\\0&0\end{bmatrix}$.

If N(T) means the nullity of T then you have to go to an infinite-dimensional space. The simplest example would be the unilateral shift on $\displaystyle \ell_2$. This is 1-1, so has zero-dimensional null space. But its adjoint is the backwards shift, which has one-dimensional kernel.