This makes sense! Let \(A = \{1,2,\ldots, 9\}\) and \(B = \{y, n\}\text{.}\) We are assigning each element of the set either a yes or a no. Or in the language of bit-strings, we would take the 9 positions in the bit string as our domain and the set \(\{0,1\}\) as the codomain.
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