2,166 reputation
11022
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location Minneapolis, MN
age 65
visits member for 3 years, 3 months
seen 13 hours ago

I am interested in closure systems. I think of them as generalizations of the convex hull operation rather than a generalization of closure in topology. See: http://www.ams.org/meetings/sectional/1058-52-28.pdf


Jul
2
awarded  Curious
Jun
7
answered How is derived the inductive step in mathematical induction?
Jun
3
reviewed Looks OK How to get Speed from Velocity with Integral
May
29
comment Study of all published works of Bertrand Russell on foundations of mathematics: Please recommend his works.
As I recall Principia is page after page after page of proofs using formal logic with few if any words in English or any other human readable language. There are good reasons why this method of mathematical exposition did not catch on.
May
27
reviewed No Action Needed What's the most combinations i can have in a matrix?
May
15
reviewed Approve suggested edit on Question about Binomial Distribution
May
15
reviewed Approve suggested edit on ask the Limit of a sequence
May
5
reviewed Reviewed How to show that $\frac{\sqrt{n-1}\Gamma((n-1)/2)}{\sqrt{2}\Gamma(n/2)}>1$.
May
4
reviewed No Action Needed Placing rooks on a $5\times 5$ board
May
3
answered What does it mean to find all solutions on the interval?
May
3
reviewed Reviewed The number of a set of irreducible projective characters vs the number of the ordinary characters of a finite group G.
May
3
revised The number of a set of irreducible projective characters vs the number of the ordinary characters of a finite group G.
Added a tag for reference request.
May
3
reviewed No Action Needed A series that converges absolutely and a bounded series
May
2
reviewed Approve suggested edit on number of lattice points in an n-ball
May
2
reviewed Looks OK What is the value of $\int x^x~dx$?
May
2
comment Lower bound on union of finite sets (inclusion-exclusion principle)
You do not need to find the exact cardinality but rather (I am guessing) the greatest lower bound. If it is just a lower bound try $0$. ;) To get the smallest possible value the sets must overlap as much as possible. Suppose the sets are ordered so that $n_{1} \leq n_{2} \leq \cdots$. Work out a cases; say up to $3$ or $4$ sets. Then try induction on the number of sets.
Apr
30
reviewed Edit How to solve fraction which is divided by decimal fraction
Apr
30
revised How to solve fraction which is divided by decimal fraction
Corrected spelling.
Apr
30
reviewed Looks OK For what values of b does the following system of modular equations have a solution?
Apr
30
reviewed Approve suggested edit on Is there a value for $\pi$ that relates to triangles?