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\begin{align*}
Plane &: \mathbb{R}^2 \mapsto \mathbb{R}^3 \\
Plane(a,b) &:= ( term_x(a,b), term_y(a,b), term_z(a,b) ) \\
term_\{_x_,_y_,_z_\} &: \mathbb{R}^2 \mapsto \mathbb{R}
\end{align*}