Symmetric Difference Independent of Order

[alf808]

Here's a clear definition of set equality. One sees that order is not explicit at all.
https://proofwiki.org/wiki/Definition:Set_Equality
Two sets are equal iff they contain the same elements:
∀x:(x∈A⟺x∈B)⟺A=B
The order of the elements in the sets is immaterial.

Is there a way to reopen this topic?
(Edited note: I eliminated the reference to commutativity and associativity of symmetric difference since it is irrelevant to set equality)

the youtube video presented in case #1358 does not demonstrate at all that ordering matters.

I think the equality of sets is independent of order. {1,2,3} = {3,2,1}
see more here: http://www.cs.odu.edu/~toida/nerzic/content/set/basics.html

Please also note that according to the site above that is also true that:
{1, 2, 3} = {3, 2, 1, 1}, that is duplications do NOT make any difference for sets.

[SaintPeter]

I've replied on the other issue, and I agree, order is not important.

However, you correctly note that:
(AΔB)ΔC = AΔ(BΔC).

Are you attempting to argue that the Bonfire is not correct? Because I believe it is easily demonstrable that it is.

[alf808]

just based on this ∀x:(x∈A⟺x∈B)⟺A=B , it's clear to me that order is NOT important. Bonfire testing is NOT correct. Although it is relevant to symmetric difference, i.e. with respect to Δ operator, I don't believe associativity AΔB)ΔC = AΔ(BΔC) is relevant to order. I should not have shown it.

[alf808]

Prescribing the order of the elements defeats the purpose of doing set theory at all. FCC either does set theory concept with symmetric difference or not at all. FCC can redefine and redesign the challenge without calling it symmetric difference. Set equality is fundamental in set theory. Why do set theory and not do set theory? it's contradictory.

[alf808]

I can "solve" the problem too. I've been doing this for a week now. Some of my code has been hacky so I can "solve" the problem or pass the test cases. But it's not my point. Why go through the pretense of doing a set theory concept? why bother with this symmetric difference corollary S∗T=(S∪T)∖(S∩T) and not bother with a set equality axiom ∀x:(x∈A⟺x∈B)⟺A=B ? If symmetric difference is not the point of the problem, then I think it should be redesigned and it not be labelled symmetric difference. If symmetric difference is the point, then set equality is fundamental and axiomatic.

[KMAN9959]

Please take me off of your emails I am getting a 100 a day

Sent from my iPhone

On Jul 28, 2015, at 6:12 PM, alf notifications@github.com wrote:

I can "solve" the problem too. I've been doing this for a week now. Some of my code has been hacky so I can "solve" the problem or pass the test cases. But it's not my point. Why go through the pretense of doing a set theory concept? why bother with this symmetric difference corollary S∗T=(S∪T)∖(S∩T) and not bother with a set equality axiom ∀x:(x∈A⟺x∈B)⟺A=B ? If symmetric difference is not the point of the problem, then I think it should be redesigned and it not be labelled symmetric difference. If symmetric difference is the point, then set equality is fundamental and axiomatic.

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[alf808]

I don't know who you are. I don't know how freecodecamp works. I couldn't
possibly have sent you 100 emails.
On Jul 28, 2015 2:32 PM, "KMAN9959" notifications@github.com wrote:

Please take me off of your emails I am getting a 100 a day

Sent from my iPhone

On Jul 28, 2015, at 6:12 PM, alf notifications@github.com wrote:

I can "solve" the problem too. I've been doing this for a week now. Some
of my code has been hacky so I can "solve" the problem or pass the test
cases. But it's not my point. Why go through the pretense of doing a set
theory concept? why bother with this symmetric difference corollary
S∗T=(S∪T)∖(S∩T) and not bother with a set equality axiom ∀x:(x∈A⟺x∈B)⟺A=B ?
If symmetric difference is not the point of the problem, then I think it
should be redesigned and it not be labelled symmetric difference. If
symmetric difference is the point, then set equality is fundamental and
axiomatic.

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Reply to this email directly or view it on GitHub.

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#1402 (comment)
.

[KMAN9959]

No you didn't everybody in the free code camp universe has I am being copied on every email every one sends. Can't you post s global email saying there is something wrong here

Sent from my iPhone

On Jul 28, 2015, at 7:17 PM, alf notifications@github.com wrote:

I don't know who you are. I don't know how freecodecamp works. I couldn't
possibly have sent you 100 emails.
On Jul 28, 2015 2:32 PM, "KMAN9959" notifications@github.com wrote:

Please take me off of your emails I am getting a 100 a day

Sent from my iPhone

On Jul 28, 2015, at 6:12 PM, alf notifications@github.com wrote:

I can "solve" the problem too. I've been doing this for a week now. Some
of my code has been hacky so I can "solve" the problem or pass the test
cases. But it's not my point. Why go through the pretense of doing a set
theory concept? why bother with this symmetric difference corollary
S∗T=(S∪T)∖(S∩T) and not bother with a set equality axiom ∀x:(x∈A⟺x∈B)⟺A=B ?
If symmetric difference is not the point of the problem, then I think it
should be redesigned and it not be labelled symmetric difference. If
symmetric difference is the point, then set equality is fundamental and
axiomatic.

—
Reply to this email directly or view it on GitHub.

—
Reply to this email directly or view it on GitHub
#1402 (comment)
.

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[aliaslam7163]

You can stop it by changing the setting from github

Sent from my iPhone

On Jul 28, 2015, at 6:32 PM, KMAN9959 notifications@github.com wrote:

No you didn't everybody in the free code camp universe has I am being copied on every email every one sends. Can't you post s global email saying there is something wrong here

Sent from my iPhone

On Jul 28, 2015, at 7:17 PM, alf notifications@github.com wrote:

I don't know who you are. I don't know how freecodecamp works. I couldn't
possibly have sent you 100 emails.
On Jul 28, 2015 2:32 PM, "KMAN9959" notifications@github.com wrote:

Please take me off of your emails I am getting a 100 a day

Sent from my iPhone

On Jul 28, 2015, at 6:12 PM, alf notifications@github.com wrote:

I can "solve" the problem too. I've been doing this for a week now. Some
of my code has been hacky so I can "solve" the problem or pass the test
cases. But it's not my point. Why go through the pretense of doing a set
theory concept? why bother with this symmetric difference corollary
S∗T=(S∪T)∖(S∩T) and not bother with a set equality axiom ∀x:(x∈A⟺x∈B)⟺A=B ?
If symmetric difference is not the point of the problem, then I think it
should be redesigned and it not be labelled symmetric difference. If
symmetric difference is the point, then set equality is fundamental and
axiomatic.

—
Reply to this email directly or view it on GitHub.

—
Reply to this email directly or view it on GitHub
#1402 (comment)
.

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[alf808]

I am absolutely confounded. I don't know who you are. Why would I post a
global email? Do you mean in a planetary scale? That sounds insane. Why? I
have very little knowledge of this organization as I've been doing this
only a week!
On Jul 28, 2015 3:32 PM, "KMAN9959" notifications@github.com wrote:

No you didn't everybody in the free code camp universe has I am being
copied on every email every one sends. Can't you post s global email saying
there is something wrong here

Sent from my iPhone

On Jul 28, 2015, at 7:17 PM, alf notifications@github.com wrote:

I don't know who you are. I don't know how freecodecamp works. I couldn't
possibly have sent you 100 emails.
On Jul 28, 2015 2:32 PM, "KMAN9959" notifications@github.com wrote:

Please take me off of your emails I am getting a 100 a day

Sent from my iPhone

On Jul 28, 2015, at 6:12 PM, alf notifications@github.com wrote:

I can "solve" the problem too. I've been doing this for a week now.
Some
of my code has been hacky so I can "solve" the problem or pass the test
cases. But it's not my point. Why go through the pretense of doing a
set
theory concept? why bother with this symmetric difference corollary
S∗T=(S∪T)∖(S∩T) and not bother with a set equality axiom
∀x:(x∈A⟺x∈B)⟺A=B ?
If symmetric difference is not the point of the problem, then I think
it
should be redesigned and it not be labelled symmetric difference. If
symmetric difference is the point, then set equality is fundamental and
axiomatic.

—
Reply to this email directly or view it on GitHub.

—
Reply to this email directly or view it on GitHub
<
#1402 (comment)

.

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#1402 (comment)
.

[KMAN9959]

It was a bit of a tongue and check comment because of your comment that I couldn't have received 100emails. I have received one hundred since you spammed me an hour ago

Sent from my iPhone

On Jul 28, 2015, at 9:23 PM, alf notifications@github.com wrote:

I am absolutely confounded. I don't know who you are. Why would I post a
global email? Do you mean in a planetary scale? That sounds insane. Why? I
have very little knowledge of this organization as I've been doing this
only a week!
On Jul 28, 2015 3:32 PM, "KMAN9959" notifications@github.com wrote:

No you didn't everybody in the free code camp universe has I am being
copied on every email every one sends. Can't you post s global email saying
there is something wrong here

Sent from my iPhone

On Jul 28, 2015, at 7:17 PM, alf notifications@github.com wrote:

I don't know who you are. I don't know how freecodecamp works. I couldn't
possibly have sent you 100 emails.
On Jul 28, 2015 2:32 PM, "KMAN9959" notifications@github.com wrote:

Please take me off of your emails I am getting a 100 a day

Sent from my iPhone

On Jul 28, 2015, at 6:12 PM, alf notifications@github.com wrote:

I can "solve" the problem too. I've been doing this for a week now.
Some
of my code has been hacky so I can "solve" the problem or pass the test
cases. But it's not my point. Why go through the pretense of doing a
set
theory concept? why bother with this symmetric difference corollary
S∗T=(S∪T)∖(S∩T) and not bother with a set equality axiom
∀x:(x∈A⟺x∈B)⟺A=B ?
If symmetric difference is not the point of the problem, then I think
it
should be redesigned and it not be labelled symmetric difference. If
symmetric difference is the point, then set equality is fundamental and
axiomatic.

—
Reply to this email directly or view it on GitHub.

—
Reply to this email directly or view it on GitHub
<
#1402 (comment)

.

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#1402 (comment)
.

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[KennethFax]

                                                                                  S                                                                                                                                                                                                   N

Sent from my iPhone

On Jul 28, 2015, at 7:17 PM, alf notifications@github.com wrote:

I don't know who you are. I don't know how freecodecamp works. I couldn't
possibly have sent you 100 emails.
On Jul 28, 2015 2:32 PM, "KMAN9959" notifications@github.com wrote:

Please take me off of your emails I am getting a 100 a day

Sent from my iPhone

On Jul 28, 2015, at 6:12 PM, alf notifications@github.com wrote:

I can "solve" the problem too. I've been doing this for a week now. Some
of my code has been hacky so I can "solve" the problem or pass the test
cases. But it's not my point. Why go through the pretense of doing a set
theory concept? why bother with this symmetric difference corollary
S∗T=(S∪T)∖(S∩T) and not bother with a set equality axiom ∀x:(x∈A⟺x∈B)⟺A=B ?
If symmetric difference is not the point of the problem, then I think it
should be redesigned and it not be labelled symmetric difference. If
symmetric difference is the point, then set equality is fundamental and
axiomatic.

—
Reply to this email directly or view it on GitHub.

—
Reply to this email directly or view it on GitHub
#1402 (comment)
.

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—Reply to this email directly or view it on GitHub.

[KennethFax]

                                                                                                                                                                                                                                                                                                                                                                                                                          Sent from my BlackBerry 10 smartphone.                                                                                                                                                                                                                From: KMAN9959Sent: Tuesday, July 28, 2015 17:32To: FreeCodeCamp/freecodecampReply To: FreeCodeCamp/freecodecampSubject: Re: [freecodecamp] Symmetric Difference Independent of Order (#1402)Please take me off of your emails I am getting a 100 a day

Sent from my iPhone

On Jul 28, 2015, at 6:12 PM, alf notifications@github.com wrote:

I can "solve" the problem too. I've been doing this for a week now. Some of my code has been hacky so I can "solve" the problem or pass the test cases. But it's not my point. Why go through the pretense of doing a set theory concept? why bother with this symmetric difference corollary S∗T=(S∪T)∖(S∩T) and not bother with a set equality axiom ∀x:(x∈A⟺x∈B)⟺A=B ? If symmetric difference is not the point of the problem, then I think it should be redesigned and it not be labelled symmetric difference. If symmetric difference is the point, then set equality is fundamental and axiomatic.

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Reply to this email directly or view it on GitHub.

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[royshouvik]

Hi @KMAN9959 Have you figured out yet that you have to stop watching the Github repository of FreeCodeCamp. I hope this solves your issue with too many emails on your inbox. Thanks.

[jhnpckr]

I think either the tests are wrong or the description of the challenge is unclear. Who gets to decide which?

[alf808]

I think to be consistent with the whole set theory challenge the tests should allow for this:
∀x:(x∈A⟺x∈B)⟺A=B , i.e. without any precribed or explicit ordering. Please I'm sorry in advanced if this is deemed a spam.

[SaintPeter]

I have submitted a pull request to resolve this issue (#1426).

My solution is to sort the user's results and then compare against a pre-sorted expected value. This ensures that any order of user generated results will always equal the test case.

Thanks to @alf808 for banging my head against this one until I understood the issue. I hope that this solution is acceptable to you.

[alf808]

@SaintPeter extremely grateful!! I will close this issue since you have a new one that's more specific. thank you again.

[SaintPeter]

I would leave it open until the Pull Request is accepted.

[alf808]

I'm still getting this error: