bio | website | |
---|---|---|
location | University of California, Berkeley | |
age | 68 | |
visits | member for | 5 years, 5 months |
seen | Mar 24 '14 at 1:18 | |
stats | profile views | 1,095 |
Jul
7 |
awarded | Nice Answer |
Apr
21 |
awarded | Good Answer |
Nov
15 |
awarded | Nice Answer |
Oct
10 |
awarded | Yearling |
Sep
30 |
awarded | Nice Answer |
Jun
25 |
awarded | Excavator |
Jan
11 |
revised |
Examples of common false beliefs in mathematics
it's -> its |
Jan
11 |
comment |
Are there smooth bodies of constant width?
I took a look at the Fillmore paper, and just before his Corollary to Theorem 2 -- which reads "Corollary. There exists an analytic hypersurface of constant width in E^n having the same group of symmetries as a regular n-simplex." -- he writes "If we imitate the construction of a Reuleux triangle . . .. Thus:" This seems to imply that he is assuming that [the intersection of four balls in 3-space, centered at the vertices of a regular tetrahedron and each with radius = the side-length of the tetrahedron] is a body of constant width. But this is known to be false. |
Dec
24 |
comment |
$SU(2)$ and the three sphere
It's not so much that you also need det(x) = 1, as that this is exactly the same as saying |a|<sup>2</sup> + |b|<sup>2</sup> = 1. |
Sep
14 |
comment |
Riemann zeta at even integers
In the functional equation for ζ(s), the term Γ(s) should be Γ(s/2), and the term Γ(1-s) should be Γ((1-s)/2). |
Aug
13 |
comment |
Irreducible homology 3-spheres that bound smooth contractible manifolds
The usual contractible 2-complex discovered by Bing is called a "House With Two Rooms", and this is not what is depicted in the image above this answer. The 2-complex depicted is not contractible (since a loop around either inner cylinder is a nontrivial 1-cycle, as is easily verified). To obtain the House With Two Rooms, one needs to add two disjoint rectangles IxI to the image, each one intersecting one inner cylinder in an interval, the outer cylinder in an interval, and the 2-complex depicted in its entire (rectangular) boundary circle. |
Mar
28 |
awarded | Yearling |
Mar
29 |
awarded | Yearling |
Feb
25 |
awarded | Nice Answer |
Jan
12 |
awarded | Nice Answer |
Oct
25 |
awarded | Nice Answer |
Aug
25 |
revised |
Infinite-dimensional complex polynomial or rational Lie algebras and their pseudogroups
changed title |
Aug
25 |
revised |
Infinite-dimensional complex polynomial or rational Lie algebras and their pseudogroups
Added note about the ease of computing formulas for the flows |
Aug
25 |
revised |
Infinite-dimensional complex polynomial or rational Lie algebras and their pseudogroups
probably -> surely |
Aug
25 |
asked | Infinite-dimensional complex polynomial or rational Lie algebras and their pseudogroups |