Solution
= Solution
Let $f(x)=x^4-6x^3+11x^2-5x$. The node <polynomial> is
$$
\omega(x)=x(x-1)(x-2)(x-3)=x^4-6x^3+11x^2-6x.
$$
It vanishes at all four nodes, so subtracting it leaves the data unchanged. Since $f(x)-\omega(x)=x$, uniqueness of <polynomial interpolation> gives
$$
\boxed{p(x)=x}.
$$