AIEEE 2006 (Offline)Question 1
Let $W$ denote the words in the English dictionary. Define the relation $R$ by $R=\{(x,y)\in W\times W\mid\text{the words }x\text{ and }y\text{ have at least one letter in common}\}$. Then, $R$ is
Sets, Relations and Function
Solution
Every word shares a letter with itself and the relation is clearly symmetric, but e.g. INK–KING share K, KING–GO share G, while INK and GO share none, so $R$ is not transitive.