Exercise 8.27

For each of the following sentences in English, decide if the accompanying first-order logic sentence is a good translation. If not, explain why not and correct it. (Some sentences may have more than one error!)

  1. No two people have the same social security number.

  2. John’s social security number is the same as Mary’s.

  3. Everyone’s social security number has nine digits.

  4. Rewrite each of the above (uncorrected) sentences using a function symbol ${SS}#$ instead of the predicate ${HasSS}#$.

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