...variables,
Frege used the word `function' where we now use the word `relation'. This was again adopted by Hilbert and Ackermann in the second edition of their book (1938). Unfortunately we also use the words `function symbol' in modern logic, but with quite a different meaning, namely such will be interpreted as a function on a domain to itself.
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...geometry,
In a letter to Hilbert at a later date he said there was no reason to prove the axioms of geometry consistent because they were true.
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...False
Frege describes the truth value of 17#17 for each of the four possible truth values of P,Q. Thus we almost have the first truth table; but there is no table, just a verbal description. Truth tables are usually attributed to Wittgenstein who was well versed in Frege's work, and had gone to study with Russell at Frege's suggestion.
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...law
In Frege's book it was written

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...have
A slight variation on this applies to 33#33, namely one gets 34#34.
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```

Stan Burris
Sat Feb 8 17:24:03 EST 1997