5,785 reputation
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visits member for 3 years, 3 months
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My real name is LI Du.

Ma Ming is my long-time pseudonym on the Internet.

I am a maths PhD student in University of Göttingen.


Dec
16
answered Prove the energy is constant in a PDE?
Dec
16
comment Don't understand proof that convergence implies Cauchy
hey, the $n$ in $x_n$ is an free variable; that is, $x_m$ is just another notation for $x_n$.
Dec
16
awarded  Caucus
Dec
10
answered Calculate the result of the following sequence.
Dec
9
comment Question about compact sets in $\mathbb{R}$
I suppose the function might be continuous.
Dec
9
answered How to prove $\lim_{x\to \infty}\Im\left(xi^{1/x}\right)=\frac{\pi}{2}$?
Dec
9
comment Notation of logarithms
then how do you write $c\lg_a b$?
Dec
2
reviewed Approve convoluted recurrence: $f(2n)=f(n)+f(n+1)+n, f(2n+1)=f(n)+f(n-1)+1$
Dec
2
reviewed Approve Evaluate $\int_{0}^{\frac{\pi}{2}} \frac{\sin^2 nx}{\sin x} \text{d}x$
Nov
29
reviewed Approve Example of endofunctor in Cat that is not a 2-functor.
Nov
29
comment Importance of Toeplitz operators?
Would the right hand of the index formula $\deg(f)$ be $\deg (f/|f|)$ or winding number of $f$?
Nov
28
reviewed Approve No perfect matching of k-regular graphs
Nov
27
comment Proof of $2^n \ge n^2 $ for $n \ge 4 $
The induction step amounts to proof $2 n^2 \ge (n+1)^2$.
Nov
27
answered line integral problem with a circle
Nov
22
comment Showing that a specific curve is regular.
if $q=0$, the curve is a constant point, thus irregular.
Nov
22
revised Showing that a specific curve is regular.
added 71 characters in body
Nov
22
answered Showing that a specific curve is regular.
Nov
22
revised Fermat's little theorem question
edited body
Nov
22
comment How to draw or plot illustrative figures?
maybe TikZ worth trying?
Nov
22
comment Basis for a line bundle
I suppose a topological trivial line bundle is not necessarily a holomorphic trivial line bundle.