$$\underset{a}{\arg\min}$$
$$\overline{y}$$
$$ |_{a}^b,\; \big|a^b,\; \bigg|{a}^b $$
$$ y = \left{ \begin{array}{l}
first\
second
\end{array} \right. $$
$$
\begin{bmatrix}
1 & x & x^2 \
1 & y & y^2 \
1 & z & z^2 \
\end{bmatrix}
$$
$$
\left|\begin{array}{}
\mathbf{i} & \mathbf{j} & \mathbf{k} \
a_1 & a_2 & a_3 \
b_1 & b_2 & b_3
\end{array}\right|
$$
$$ A \cap B=\varnothing $$
$$ A \cup B=\Omega $$
$$ \approx $$
$$ \frac{\partial z}{\partial x} $$
$$ \equiv $$
$$ \Leftrightarrow $$