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Errata in the textbook

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robanaurochs

Errata in the textbook
January 11, 2009 08:40PM

Registered: 18 years ago
Posts: 1,424
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The proof at the bottom of p21

Line 1 is not labeled as a premise yet it's the only one. There are two arguments running side-by-side from line 2 (I assume this is to save space). Both of these arguments on line 2 (not p in the first argument, and q in the second argument) begin with a premise. This is an error; these are not premises but rather assumptions.

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Anonymous User

Re: Errata in the textbook
January 14, 2009 04:32PM

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robanaurochs Wrote:
-------------------------------------------------------
>This is an error;
> these are not premises but rather assumptions.

A premise is an assumption,
I havent read the book yet though so I guess I cant say much about the errata

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robanaurochs

Re: Errata in the textbook
January 14, 2009 07:30PM

Registered: 18 years ago
Posts: 1,424
Rating: 0

In a sense, you're right but I'm taking it from the point of view of "Who's assumption". To me, a premise is an assumption we're allowed to take since it was given to us. The assumptions we right in our proofs are those we've made ourselves and they must be discharged before we can claim to have proven the conclusion.