## Tagged Questions

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### Resultant of 3 system polynomials with 3 variables.

Let say I have a system of 3 polynomials, f1(x,y,z), f2(x,y,z), f3(x,y,z). How to find the resultant of these 3 polynomials. What I meant is, is there any special method to do this …
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### Importance of separability vs. second-countability

For me second-countability always felt like to be the more important and fundamental concept from general topology than separability. I wonder whether there are any points which ca …
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### Are all sets totally ordered ?

The question is the title. Working in ZF, is it true that: for every nonempty set X, there exists a total order on X ? If it is false, do we have an example of a nonempty set t …
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### The sufficient condition of the Neumann problem

How can we prove that if $\int_U{f}=0$,then the homogeneous Neumann problem $\Delta u=f$on U,and $\frac{\partial u}{\partial n}=0$ on $\partial U$ has a weak solution in $H^1(U)$? …
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### Is there a better function (linear or even a projection)?

Let $A$ be a finite $n$-element set. Let $\mathbb R^A$ be an $n$-dimensional Euclidean space (with the ordinary Euclidean distance). Let $X$ be an arbitrary topological space. Cons …
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### Is there any result concerning on the metric dimension of inverse limit?

To be specific, my question is as follows: Question: Let X be an inverse limit of compact metric spaces (X_i, d_i), then does it hold dim(X, d) \leq sup_i {dim (X_i, d_i)} for so …
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### Another colored balls puzzle (part II)

The same colleague as in http://mathoverflow.net/questions/130489/another-colored-balls-puzzle asked me the following variant which she called "part II". Imagine you have $n$ ball …
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### Proof of the weak Goldbach Conjecture

What are the main ideas of Harald Helfgott's proof that all odd $n \geq 5$ is the sum of 3 primes?
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### What math institutes offer research in pairs/research in teams?

Some math institutes offer programs in which a small number of researchers are enabled to meet at the institute for a week or more. A list seemed as if it could be useful.
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### Free resolution for Lie algebras (reference)

What is a reference for the subject of "free resolutions for Lie algebras"? Does the term "standard resolutions" means "free resolutions"? What is a "bar resolution"? Is there o …