55 reputation
4
bio website
location
age
visits member for 2 years, 5 months
seen Nov 9 '13 at 23:37

Jun
28
revised Is the intersection of every non-empty family of inductive sets equal to the intersection of every inductive set?
deleted 1 characters in body
Jun
27
comment Is the intersection of every non-empty family of inductive sets equal to the intersection of every inductive set?
I don't see why this general version was needed, and my question was about finding a reason for its presence.
Jun
27
awarded  Editor
Jun
27
revised Is the intersection of every non-empty family of inductive sets equal to the intersection of every inductive set?
added 10 characters in body
Jun
27
comment Is the intersection of every non-empty family of inductive sets equal to the intersection of every inductive set?
It's me that should have added the sentence preceding these : "We shall say, temporarily, that a set A is a successor set if [...]"
Jun
27
asked Is the intersection of every non-empty family of inductive sets equal to the intersection of every inductive set?
Dec
30
comment I shouldn't be able to prove the power-set of union is equal to union of power-sets.
Thanks. The absence of quantifier can be explained by the fact that this problem emerged in the context of Hamos' Naive Set Theory, which makes no use of quantifier and very little of first order logic. It was asked to prove that $P(A) \cup P(B) \subset P(A \cup B)$, and I decided to test the converse, which we aren't asked to do.
Dec
30
awarded  Supporter
Dec
30
accepted I shouldn't be able to prove the power-set of union is equal to union of power-sets.
Dec
29
asked I shouldn't be able to prove the power-set of union is equal to union of power-sets.
Jul
7
comment Understanding this summation identity
I guess that when manipulating new symbols (the Sigma notation isn't exactly new to me but it had never been center stage) their complete meaning isn't immediately apparent. I didn't see it concretely.
Jul
7
awarded  Scholar
Jul
7
accepted Understanding this summation identity
Jul
7
comment Understanding this summation identity
Thanks. Quite helpful.
Jul
7
comment Understanding this summation identity
Didn't expect answers which would come as quickly and be as good. Thanks.
Jul
7
awarded  Student
Jul
7
asked Understanding this summation identity