375 reputation
112
bio website wamath.sinaapp.com
location china
age 27
visits member for 2 years, 10 months
seen Jul 18 at 2:03

I am a postgraduate student in Southwest University, Chongqing, China, majored in elementary mathematics and interested fields include Riemannian Geometry and Elliptic Differential Equation. I always confused about the textbooks, so I would like have a discussion with anybody on the net.


Jul
8
comment Monotonically approximate $L^p$ function by step function
That's it! I just forgot what I have learned in my mind.
Jul
8
accepted Monotonically approximate $L^p$ function by step function
Jul
8
comment Monotonically approximate $L^p$ function by step function
By the way, Can you give some exactly reference or raise an answer here, of your second TRUE? I believe it will be useful to me, although the step function is replaced by simple function.
Jul
8
comment Monotonically approximate $L^p$ function by step function
@PhoemueX The step function usually means simple function on Cubes( intervals in $R^1$ case).
Jul
8
comment Monotonically approximate $L^p$ function by step function
I think you have some misunderstanding about the approximate, I think we should allow $g\leq f$ holds in the a.e. sense. In that case, we can take $f_k\equiv 1$ on $[0,1]$ as step function in your counterexample on $[0,1]$.
Jul
8
comment Monotonically approximate $L^p$ function by step function
I googled and get no results. And my knowledge of proof of the classical fact can not modify easily to get a proof of my requirement.
Jul
8
asked Monotonically approximate $L^p$ function by step function
Jul
2
awarded  Curious
Jul
2
accepted A problem concern about the relationship between homotopy groups.
Jul
2
comment A problem concern about the relationship between homotopy groups.
Thanks a lot! It really helps me, I mean as a beginner to algebra topology.
Jun
18
comment A problem concern about the relationship between homotopy groups.
@QiaochuYuan I try to work with your hint, but still can't get it, so would you please post an answer?
Jun
17
comment A problem concern about the relationship between homotopy groups.
@SanathDevalapurkar sorry, already corrected.
Jun
17
asked A problem concern about the relationship between homotopy groups.
May
5
comment Reconsideration of a homework
of course I can work out the solution by following the hint, my question is how the get the hint, that's why I call my question "re-consideration".
May
2
asked Reconsideration of a homework
Apr
23
revised the preimage of a continuous function is measurable?
added 139 characters in body
Apr
23
revised the preimage of a continuous function is measurable?
added 9 characters in body
Apr
23
asked the preimage of a continuous function is measurable?
Apr
12
asked The derivative of convolution
Dec
26
asked When is the Lie algebra of the center of Lie group the center of its Lie algebra