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 Yearling
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Feb
14
revised Conformal mapping from square to disk as inverse of hypergeometric function
added 13 characters in body
Feb
11
answered Conformal mapping from square to disk as inverse of hypergeometric function
Oct
21
comment Topology of SL(2,R)
It isn't a complex curve - the equality $|a|^2 - |b|^2 = 1$ is one real condition, not one complex condition. So you expect the group to be three real-dimensional. By the way, you are very close to having a direct answer using the first description you gave. Try to show that $X^2 - z^2 - w^2 = 1$ describes a copy of $\mathbb{R}^2$.
Sep
17
comment Seeking a good book or site describing the 3-sphere
Very nice pictures!
Sep
17
comment Algebraic Topology Question Regarding a Space
@ Sen - Just a quick remark. Prof Brown's remarks are not a proof but rather a sequence of hints. We would have to provide the claimed homeomorphisms with $A$ and with $B$, and check that the induced gluing of $\partial A$ to $\partial B$ agrees with $f$. But these are exercises "left to the reader". :)
Aug
21
comment flat manifold, curvature and the circle
You are confusing two notions of curvature. There is the geodesic curvature of a circle (which depends on its embedding in the plane) and the Riemannian curvature of the circle (which is intrinsic).
Aug
21
answered Question of maps in Mayer-Vietoris sequence
Aug
18
awarded  Yearling
Jul
15
revised Figure eight knot is not a torus knot
typo
Jun
20
revised Orientable Surface Covers Non-Orientable Surface
added 4 characters in body
Jun
20
answered Orientable Surface Covers Non-Orientable Surface
Jun
9
revised Embedding covers of manifolds
added adjective
Jun
9
revised Embedding covers of manifolds
added closed examples.
Jun
9
answered Embedding covers of manifolds
Feb
14
reviewed Approve Periodic Function With A Given Functional Equation
Feb
14
revised Mapping Class Group
fixed typo
Jan
26
reviewed Reject Square root of complex number in polar or rectangular form
Jan
26
comment Evaluate the sum $x + \frac{x^3}{3} + \frac{x^5}{5} + … $
What do you get if you set $x = 0$? This kind of checking of special values is useful for quickly detecting mistakes.
Jan
26
answered Why is SO(3) not $S^1 \times S^2$? (Where is the mistake?)
Jan
11
reviewed Approve Find values of $a$ for which $\sum\limits_{n=1}^\infty n^{-a}\log ( 1 + n^{-1}) $ converges