deletions | additions       diff --git a/A_set_A_is_called__.tex b/A_set_A_is_called__.tex  index e472b60..aa24b36 100644  --- a/A_set_A_is_called__.tex  +++ b/A_set_A_is_called__.tex 
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Show that if the sets A, B are both countably infinite then so is the Cartesian product $A\times B:=\{(,a,b): a\in A, b\in B\}$.    \[A x B \in \{(a,b) {(a,b)  | A_i \in A, B_i \in B} \] \[ A $A$  is the set {A_1,A_2,A_3, ${A_1,A_2,A_3,  ... A_i} \]  \[B A_i}$   $B$  is the set {B_1, ${B_1,  B_2, B_3 ... B_i} \] $