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location Unknow Galaxy
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visits member for 2 years, 4 months
seen Dec 20 '13 at 18:33

A student in Philosophy but also curious in many fields.


I don't know,

But I want to know.


Oct
15
awarded  Notable Question
Jul
2
awarded  Curious
Jul
2
awarded  Inquisitive
Jun
5
awarded  Yearling
Dec
11
accepted Is there any countable ordinal number which has a member undefinable?
Nov
9
awarded  Popular Question
Aug
4
comment Is there any countable ordinal number which has a member undefinable?
Helpful, thank you.
Jul
16
comment Is there any countable ordinal number which has a member undefinable?
@CarlMummert I was trying to understand you. Would you please show me more detail? Do these models of ZFC, which every set is definable over the model, themselves may have uncountable(outside) many subsets? Or the cardinalities of their powersets are all at most countable(outside), but some of which are uncountable(inside)? Besides, what about $(V,<)$?
Jul
16
comment Is there any countable ordinal number which has a member undefinable?
It's nice for me, thank you.
Jul
16
revised Is there any countable ordinal number which has a member undefinable?
highlight
Jul
16
comment Is there any countable ordinal number which has a member undefinable?
@CarlMummert "There are models of ZFC in which every set is definable over the model". Did you mean definable with parameters, or just definable(without parameters)?
Jul
16
asked Is there any countable ordinal number which has a member undefinable?
Jul
3
comment What's correspondence between the model theoric and the set theoric kernel of homomorphism?
Okay, it is right now.
Jul
2
comment What's correspondence between the model theoric and the set theoric kernel of homomorphism?
Thank you for answering and sorry for late commenting as I'm in traveling yesterday. I have a question: do you mean $ker(h)$ the set-theoric kernel if $h$? If so, then $ker(Id_{\mathfrak{A}})=Id_{\mathfrak{A}} \ne \emptyset$ whenever $\mathfrak{A}$ is not empty, but $Id_{\mathfrak{A}}$ is an automorphism, hence an embedding. Thus $\ker_m(Id_{\mathfrak{A}})=diag(\mathfrak{A})$ but $ker(Id_{\mathfrak{A}}) \ne \emptyset$ in cases $\mathfrak{A}$ is not empty...
Jun
30
revised What's correspondence between the model theoric and the set theoric kernel of homomorphism?
clearify and retag
Jun
23
comment What's correspondence between the model theoric and the set theoric kernel of homomorphism?
@kahen Thank you for your suggestion.
Jun
23
revised What's correspondence between the model theoric and the set theoric kernel of homomorphism?
patch
Jun
23
comment What's correspondence between the model theoric and the set theoric kernel of homomorphism?
@tomasz Okay, I have clarified my post.
Jun
23
revised What's correspondence between the model theoric and the set theoric kernel of homomorphism?
elaboration
Jun
22
revised What's correspondence between the model theoric and the set theoric kernel of homomorphism?
clearify