question for discrete mathematics
- Thread starter Dayi
- Start date
Steven G
Elite Member
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Welcome to the forum.
If you had read the guidelines to the forum you would have known that we do not solve math problems for posters on this forum. After all the name of the forum is freemathhelp.com. There are helpers on this forum who are willing to help you solve your problem but you need to explain where you are stuck and show post the work which you have done so far. So please read the guidelines, follow them and then post back.
If you had read the guidelines to the forum you would have known that we do not solve math problems for posters on this forum. After all the name of the forum is freemathhelp.com. There are helpers on this forum who are willing to help you solve your problem but you need to explain where you are stuck and show post the work which you have done so far. So please read the guidelines, follow them and then post back.
pka
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Here is what you have posted.
For every \(n\in\mathbb{N}\) if \(A_n=(n,n+1)\cap Q\),
if gives to \(A=\left\{A_n\right\}_{n\in\mathbb{N}}\) family
you have to write and explain selection function
for \(B=A\cup\left[P(N)\setminus\{\emptyset\}\right]\)
Speaking only for myself, I have not a clue what that means.
I say that having taught set theory & discrete mathematics for a long time.
I think that you need to clean up the English rendering.
More importantly you need to define the terms and explain exactly what is being asked for.
By \(P(N)\) do you mean powerset of \(\mathbb{N}~?\)
By selection function do you mean choice function?
If so what is your understanding of such a function?
For every \(n\in\mathbb{N}\) if \(A_n=(n,n+1)\cap Q\),
if gives to \(A=\left\{A_n\right\}_{n\in\mathbb{N}}\) family
you have to write and explain selection function
for \(B=A\cup\left[P(N)\setminus\{\emptyset\}\right]\)
Speaking only for myself, I have not a clue what that means.
I say that having taught set theory & discrete mathematics for a long time.
I think that you need to clean up the English rendering.
More importantly you need to define the terms and explain exactly what is being asked for.
By \(P(N)\) do you mean powerset of \(\mathbb{N}~?\)
By selection function do you mean choice function?
If so what is your understanding of such a function?
pka
Elite Member
- Joined
- Jan 29, 2005
- Messages
- 11,971
That is fine: for every family of sets there is a choice function.
But what are we to do with it? We know that it exists, but to what end?
That is the part of this post you fave failed to make clear.