Reputation
2,069
Top tag
Next privilege 2,500 Rep.
Create tag synonyms
Badges
2 14 37
Impact
~42k people reached

  • 0 posts edited
  • 0 helpful flags
  • 80 votes cast
Aug
13
comment Intersection of a non-empty set of natural numbers (set-theoretic definition) gives an element of that set?
Wait a second, E is not a set of ordinals, E is a set of natural numbers!
Aug
13
comment Intersection of a non-empty set of natural numbers (set-theoretic definition) gives an element of that set?
Yes, we've proved this already.
Aug
13
asked Intersection of a non-empty set of natural numbers (set-theoretic definition) gives an element of that set?
Aug
12
comment Prove: If $E$ is a nonempty subset of natural numbers , then there exists an element $k$ in $E$ such that $k\in$ m for any $m$ in $E$ and$m \ne k$
I got this far, but I couldn't figure out how to prove that the intersection of E is an element of E. Any hints on this?
Jul
2
awarded  Curious
May
31
awarded  Nice Question
May
17
comment Is there a connection between uncountable sets and exponential growth?
Thanks. Should I close this question? (It doesn't really make sense anymore)
May
17
comment Is there a connection between uncountable sets and exponential growth?
Interesting... a few clarifications: (1) how did you formalize the notion of a "limit" here, (2) is there a concrete example of an element that's in the Cantor set but not in $C_n$ for any $n$, and (3) can you please give some more context for the last expression?
May
17
asked Is there a connection between uncountable sets and exponential growth?
May
17
comment Baby Rudin 2.26 Infinite subsets with limit points implies compactness
+1, I also had trouble with this part of the problem, and your answer was extremely helpful. My original strategy was to write each $U \in \mathscr{U}$ as a union of $B \in \mathscr{B}$, and then show that the collection of all possible unions of $B \in \mathscr{B}$ is countable. Oops--this collection is actually uncountable.
May
4
comment 6 keys and a door( probabilities)
What have you tried so far? Can you break the problem down into smaller parts? Can you think of a simpler version of the problem that you can try solving first?
Apr
10
awarded  Popular Question
Mar
12
awarded  Notable Question
Dec
18
awarded  Yearling
Nov
15
awarded  Notable Question
Oct
17
awarded  Nice Question
Aug
12
awarded  Good Question
May
7
awarded  Popular Question
Jan
30
awarded  Popular Question
Dec
18
awarded  Yearling