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Recently retired from Cambridge Philosophy Faculty, interested in logic and philosophy of maths.

I waste time on twitter @PeterSmith (http://twitter.com/PeterSmith/)

For more about me, and links to my blog and website, see http://www.logicmatters.net/about/


1d
comment Olympiad-style question about functions satisfying condition $f(f(f(n))) = f(n+1) + 1$
Thank you! Yes, if not exactly magical, looks the sort of qn you need to tackle with a repertoire of known techniques for questions of this type up your sleeve.
1d
revised Olympiad-style question about functions satisfying condition $f(f(f(n))) = f(n+1) + 1$
edited tags
1d
asked Olympiad-style question about functions satisfying condition $f(f(f(n))) = f(n+1) + 1$
Jan
21
reviewed Close Formal language and set theory
Jan
20
comment Do hom-sets really live in the category Set?
(And surely having urelements would muck up the usual story about terminal objects that applies in Set.)
Jan
20
comment Do hom-sets really live in the category Set?
I like my set theories to have urelements! It's a natural way to think of sets. But not what students usually encounter. Are you saying we are supposed to think of Set as e.g. a category corresponding to ZFU? Which most students reading an intro cat theory book have probably never heard of?
Jan
20
revised Do hom-sets really live in the category Set?
added 217 characters in body
Jan
20
asked Do hom-sets really live in the category Set?
Jan
7
comment Negation of quantifiers
You misunderstand: my book! :-) Peter Smith, An Introduction to Gödel's Theorems (CUP, 2nd edition 2013).
Jan
7
comment Negation of quantifiers
We've looked at the two cases, where $Q_{n+1}$ are respectively $\exists v$ and then $\forall v$ -- it has to be one or the other! (The book, as I said, is my Gödel book -- I copied a chunk to avoid retyping!)
Jan
7
answered Negation of quantifiers
Jan
3
revised Translating Mathematical Statements into Statements Involving Nested Quantifiers
added 486 characters in body
Jan
3
answered Translating Mathematical Statements into Statements Involving Nested Quantifiers
Jan
3
revised For which subsystems T of 2nd order arithmetic is there a model of T + $\neg$Con(T)?
added 2 characters in body
Jan
3
answered For which subsystems T of 2nd order arithmetic is there a model of T + $\neg$Con(T)?
Jan
1
awarded  Nice Answer
Jan
1
revised How much math does one need to know to do philosophy of math?
added 72 characters in body
Jan
1
revised Is the “domain of discourse” in axiomatic set theory also a “set”?
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Dec
31
revised Is the “domain of discourse” in axiomatic set theory also a “set”?
added 63 characters in body
Dec
31
answered Is the “domain of discourse” in axiomatic set theory also a “set”?