# There are two questions that are both attempt to prove that P=NP, but one got 2 upvotes and the other got -4 downvotes. Why?

This question is an attempt to prove P=NP.

This question is also an attempt to prove P=NP.

The first question got 2 upvotes, it is not closed, even not on hold and not considered off-topic. It also has 1 answer.

The second question got -4 downvotes, it is closed and considered off-topic because it is an attempt to prove P=NP and it has no answers at all.

Then why the first question is not closed? Why it is even not on hold? Why it is not off-topic? Why it has one answer? It is also an attempt to prove that P=NP, isn't? What is the matter and meaningful difference between the two that makes the first question better than the other?

• I don't know why who votes what, but note that voters are subjective. Jan 28, 2018 at 9:34
• – D.W. Mod
Jan 29, 2018 at 4:01

(For the record, I didn't vote on either questions)

Allow me to give a 'critique' of both questions:

For the first question:

First ten paragraphs explain a method to use Karnaugh maps to solve 3SAT. Then, 2 examples are given where this method works well and finally the question asks whether this method would work in general.

The question is a bit lengthy, but in general, it is on point.

For the second question:

The first ten paragraphs explain an interpretation of SAT and how to apply induction. This part could already lead some to down-vote, given that this 1. doesn't give any information about your question 2. anyone capable of answering this question knows about SAT and induction. Personally, I'd just scrap it or at least shorten it to one paragraph.

The rest of question explains the method and argues it could be efficient.

So, IMO, the first question is better, as it doesn't bore the reader in the first ten paragraphs by only explaining non-trivial background. Additionally, the examples are useful, as they show that the method may have some merit. Note that my critique is purely on the presentation of the question, which can always be improved. It is possible that the second question is also worse in content than the other, but I can't really evaluate that.

As for the reason why people vote, that's anyone's guess, as Raphael notes. But it could be the case that, as David Richerby states in this comment, that while most users are tolerant to a few questions about (most-likely incorrect) proofs about P vs NP, they don't like handling many of them. So, the down-votes could also be a discouragement to post similar question. However, this is just a guess. The only way to know is to ask the down/close-voters themselves.

• "The only way to know is to ask the down/close-voters themselves." They say that the second question (with induction method) asks if P=NP and that's the only reason why they decided to downvote it and close it. The first question (with karnaugh maps method) also asks exactly the same question (if P=NP) and nobody downvoted it and closed it. This seems pretty unfair.
– user82913
Feb 2, 2018 at 18:08

The P-vs-NP question has a long history of attracting laypeople trying to solve it with usually naive methods. If they don't even bother to present their attempt in suitable terms, and/or are resilient to critique, they are called "cranks". They will usuaully reject responses that don't agree with them, and refuse to engage in scientific discourse.

All active members on this site have dealt with such people at some point or another, and it has been decided that we don't want to entertain them. Their average contribution to the P-vs-NP question is zero, and reading through lengthy expositions of sub-undergrad material wastes precious time better used on other posts.

On the other hand, a well-presented (partial) proof attempt or idea may have a clear, illustrative answer. Some of our regular users take joy in engaging in productive discussion with such askers, even though they have to assume that the attempt probably doesn't work. Which posts they engage with is 100% up to their discretion. I would be surprised if they had any clear policy, even individually; it probably depends on what tickles their fancy. And that is completely okay. Everybody is here on their own leisure, and nobody is entitled to others' time.

Now, I have not read either of the two questions you link in detail, so I couldn't comment on which side (cranky-boring or interestingly-wrong) either falls. There is certainly a grey area in between, and votes might depend on who reads a question first and which mood they are in. That's because everybody here is human.

I encourage you to find out what the problem was with your question, engage in civilized discussion any expert who's willing (without pestering those unwilling). Then try to post a better question.

• Some CS journals receive so many P vs NP attempts that they has to create special policies to limit the "spam". E.g., (quoting) "no author may submit more than one such paper to JACM, ACM Trans. on Algorithms, or ACM Trans. on Computation in any 24-month period"
– chi
Feb 3, 2018 at 17:40