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brainjam
  • Member for 13 years, 11 months
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8 votes
2 answers
413 views

Is there a geometric construction that finds the intersection of two conics, given only five points on each?

7 votes
4 answers
204 views

For a recursion based on $x+y+z+2\sqrt{xy+yz+zx},$ does what happens in $\mathbb Z\left[\sqrt n\right]$ stay in $\mathbb Z\left[\sqrt n\right]$?

7 votes
1 answer
272 views

Show that the locus of a point in this geometric construction is a conic

7 votes
1 answer
197 views

Is there a name or a reference for these aperiodic rhomboidal tilings?

5 votes
1 answer
287 views

Is there an explanation for the patterns formed by the binomial coefficients $\binom{n+d-1}{d}\pmod{512}$?

5 votes
3 answers
775 views

Polygonal billiards and uniform distribution

5 votes
1 answer
115 views

Reference request: A specific book on homotopy and covering spaces

4 votes
1 answer
91 views

Conic chords projected by point $P$ form a quadrilateral whose vertex pairs are collinear with $P$

4 votes
0 answers
253 views

Synthetic construction of common self-polar triangle for two non-intersecting ellipses

3 votes
1 answer
138 views

Polynomial root finders with consistent root ordering

2 votes
1 answer
78 views

How many irrationals $x$ appear infinitely often in this set of open intervals?

2 votes
0 answers
128 views

Combinatorial analog of holonomy on a planar graph with quadrilateral faces

1 vote
2 answers
835 views

Complete quadrilateral: projective version of Newton-Gauss line

1 vote
1 answer
185 views

Errata for $\mathrm{\TeX}$ version of Thurston's 'The Geometry and Topology of Three-Manifolds'

0 votes
1 answer
54 views

Ratio of products of line segments

0 votes
1 answer
74 views

Jacobi sn: Does $w=\operatorname{sn}(z,m)$ send the line $\operatorname{Im}(z)=K'/2$ to the circle $\left \|w^4 \right \|=1/m?$

0 votes
3 answers
165 views

Elementary examples of pointwise sequential closures that are not pointwise closed

0 votes
2 answers
216 views

Uniform closures are uniformly closed but pointwise closures might not be pointwise closed