et X be the set of strings over $\{$a$,$ b$\}$ of length $4$ and let Y be the set of

strings over $\{$a$,$ b$\}$ of length $3.$ Define a function f from X to Y by the rule

f $(\backslash$alpha $)=$ string consisting of the first three characters of $\backslash$alpha $.$

$1.$ What ordered pair$($s$)$ would we have to include in the set f in order to

make it defined by the rule?

f $=\{(($aaab$,$ aaa$),($aaba$,$ aab$),($abaa$,$ aba$),($baaa$,$ baa$),($aabb$,$ aab$),($abab$,$ aba$),($abba$,$ abb$),$

$($baab$,$ baa$),($baba$,$ bab$),($bbaa$,$ bba$),($bbba$,$ bbb$),($bbab$,$ bba$),($babb$,$ bab$),($abbb$,$ abb$)\}$