\begin{align*} A \times B = \{ \amp (a_1, b_1), (a_1, b_2), (a_1, b_3), \ldots (a_1, b_n),\\ \amp (a_2, b_1), (a_2, b_2), (a_2, b_3), \ldots, (a_2, b_n),\\ \amp (a_3, b_1), (a_3, b_2), (a_3, b_3), \ldots, (a_3, b_n),\\ \amp \vdots\\ \amp (a_m, b_1), (a_m, b_2), (a_m, b_3), \ldots, (a_m, b_n)\} \end{align*}
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