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7h
comment How many ways can we totally order a set $X$ (but not necessarily the whole set $X$, perhaps just a subset) up to isomorphism?
@AndresCaicedo, okay I'll have a think about it. Probably just end up asking another question at some point.
9h
comment How many ways can we totally order a set $X$ (but not necessarily the whole set $X$, perhaps just a subset) up to isomorphism?
@AndresCaicedo, hey any idea what the answer is for scattered linear orderings?
22h
comment How many ways can we totally order a set $X$ (but not necessarily the whole set $X$, perhaps just a subset) up to isomorphism?
@AndresCaicedo, thanks. I get it now.
23h
asked How many ways can we totally order a set $X$ (but not necessarily the whole set $X$, perhaps just a subset) up to isomorphism?
1d
accepted Is there always a bijection between a universe of set theory and its ordinal numbers?
1d
comment How to prove that for finite, nonempty sets $A,B$ $|A \times B| = |A|\cdot|B|$
Pretty sure that is the definition of $|A|\cdot|B|$. You just need to check that the definition is well-defined. i.e. Basically, just assume you have three sets $A,A',B$ and a bijection $f : A \rightarrow A',$ and produce a bijection $A \times B \rightarrow A' \times B$. Then just say that "the corresponding argument for $B$ is similar."
1d
asked General question: what happens if we replace the regularity stipulation in GCH with other conditions?
2d
comment Is it possible that “A counter-example exists but it cannot be found”
@TrevorWilson, I'm not sure I follow, so let me take a look at Hamkin's stuff and I'll get back to you.
2d
comment Is it possible that “A counter-example exists but it cannot be found”
@TrevorWilson, surely we should be considering models of second-order set theory, i.e. $\mathrm{ZFC2}$ for this question. Otherwise, the model's real line needn't be the true real line relative to the ambient universe.
2d
comment Arbitrary (i.e. not necessarily finite-dimensional) vector spaces; reference request.
@AsafKaragila, not really sure man, I was just under the impression that a lot of linear algebra falls apart. Probably, this impression is baseless,
2d
accepted Confusion about cofinality
2d
comment Arbitrary (i.e. not necessarily finite-dimensional) vector spaces; reference request.
Thanks for the info, +1.
2d
asked Arbitrary (i.e. not necessarily finite-dimensional) vector spaces; reference request.
Apr
14
accepted When solving a DE, what should our premises be?
Apr
14
comment Modern book on Gödel's incompleteness theorems in all technical details
Peter Smith's Introduction to Godel's Theorems is a readable introduction that includes the sort of technical details you seem to be interested in; however if you want "each and every technical aspect" it may not be sufficient. At the very least, its a good place to start.
Apr
14
comment Converting statements with term 'only' and 'any' to predicate logic
"Only dogs are mammals" becomes "every mammal is a dog."
Apr
14
revised Is there a traditional name for the “eigenspace” function?
added 1 characters in body
Apr
14
comment Is there a traditional name for the “eigenspace” function?
@lhf, thanks. $\;\!$
Apr
14
comment Is there a traditional name for the “eigenspace” function?
@lhf, its very hard to learn more about a function if you do not know its name.
Apr
14
revised Is there a traditional name for the “eigenspace” function?
deleted 5 characters in body