0 votes 0 votes Suppose that $S_1$ and $S_2$ are countable sets. Show that then $S_1\cup S_2$ and $S_1 \times S_2$ are also countable. Theory of Computation peter-linz peter-linz-edition5 theory-of-computation turing-machine proof + – Rishi yadav asked Apr 2, 2019 Rishi yadav 124 views answer comment Share Follow See all 0 reply Please log in or register to add a comment.