4. (20 points) Arrange the numbers $\Psi, \Omega, \Theta$ in non-increasing order, if

$$
\begin{aligned}
& \Psi=\frac{1}{2} \cdot(1+2-3-4+5+6-7-8+\ldots-2012) \\
& \Omega=1-2+3-4+\ldots-2014 \\
& \Theta=1-3+5-7+\ldots-2015
\end{aligned}
$$
Answer: $\Theta, \Omega, \Psi$.

Solution:

$$
\begin{gathered}
\Psi=\frac{1}{2} \cdot(-4) \cdot 503=-1006 \\
\Omega=(-1) \cdot 1007=-1007 \\
\Theta=(-2) \cdot 504=-1008
\end{gathered}
$$