Exercise $3\mathrm{.}4.+2pts$ A binary relation $R$ is called asymmetric if aRb$=>$bRa for every $a,$binA.

$($a$)$ Draw the arrow$-$diagram of a relation on the set $A=\{1,2\},$ which is antisymmetric, but not asymmetric.

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$($b$)$ Draw the arrow$-$diagram of a relation on the set $A=\{1,2\},$ which is antisymmetric and asymmetric.