Comments on: Corrections http://www.logicmatters.net Logic, enthusiasms, sceptical thoughts, and a little LaTeX geekery Mon, 06 Feb 2012 19:23:02 +0000 hourly 1 http://wordpress.org/?v=3.1 By: Alfredo http://www.logicmatters.net/igt/corrections/comment-page-1/#comment-13422 Alfredo Sat, 22 Oct 2011 09:41:09 +0000 http://www.logicmatters.net/?page_id=634#comment-13422 IGT, p. 134, R12, Proof: (sorry for the lack of symbols!) Var(n) = def (there is an x < = n) (n = 2 raised to 2x) According to this definition, it seems to me, "Var(1)" is true: 0 is < = 1, and 1 = 2 raised to 2 times o. But 1 is not the g.n. of a variable! So perhaps one should write: Var(n) = def (there is an x < = n) (n = 2 raised to 2x AND x is not 0). If I am right, this is a correction, if I am wrong, it is a question (why is your definition correct?) Many thanks for your wonderful book! I look forward to the second edition (...and as I have written a few weeks ago, I would like to know how to prove that Sent(n) and Axiom(n) are p.r: the missing links to fully satisfy an enthusiast completist) IGT, p. 134, R12, Proof: (sorry for the lack of symbols!)

Var(n) = def (there is an x < = n) (n = 2 raised to 2x)

According to this definition, it seems to me, "Var(1)" is true: 0 is < = 1, and 1 = 2 raised to 2 times o.
But 1 is not the g.n. of a variable!
So perhaps one should write:

Var(n) = def (there is an x < = n) (n = 2 raised to 2x AND x is not 0).

If I am right, this is a correction, if I am wrong, it is a question (why is your definition correct?)

Many thanks for your wonderful book!
I look forward to the second edition (…and as I have written a few weeks ago, I would like to know how to prove that Sent(n) and Axiom(n) are p.r: the missing links to fully satisfy an enthusiast completist)

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