0 votes 0 votes i am not able to understand the proof. How we reached statement 2 from statement 1 as I have marked in the picture (right side) Can some one elaborate? Mathematical Logic set-theory&algebra discrete-mathematics + – Sandy Sharma asked Mar 14, 2019 Sandy Sharma 1.8k views answer comment Share Follow See all 0 reply Please log in or register to add a comment.
0 votes 0 votes Let $a1 \in A$ and $a1 \notin B$, so then, $(a1,a1)\notin (A \times B)\cup(B \times A)$, but $(a1,a1) \in (A \cup B) \times (A \cup B)$. So we can clearly say that (i) is false. and you have caught the error in the proof correctly.👍 Ashish Goyal answered Mar 14, 2019 Ashish Goyal comment Share Follow See all 0 reply Please log in or register to add a comment.