260 reputation
7
bio website
location
age
visits member for 7 months
seen May 14 at 6:49
stats profile views 59

May
14
accepted characterization of coherent risk measures
May
13
asked characterization of coherent risk measures
May
4
accepted reasonable asymptotic elasticity in utility maximization (paper by Kramkov / Schachermayer)
Apr
29
comment reasonable asymptotic elasticity in utility maximization (paper by Kramkov / Schachermayer)
I'm struggling with the details. If you would provide these small technicalities for point one and also for point 2 I accept your answer an you will get the bounty.
Apr
29
comment reasonable asymptotic elasticity in utility maximization (paper by Kramkov / Schachermayer)
Sorry I am still unsure about these two points. I try to figure out 1) by myself. But for point two: I do not understand your last comment. I still stuck on uniformity.
Apr
27
comment reasonable asymptotic elasticity in utility maximization (paper by Kramkov / Schachermayer)
About the second question: I've never heard about locally uniformly strict convex functions. All I know is a uniform convex space. I searched the web without succes. Could you please give me a reference. I know that $V(\frac{a+b}{2})\le \frac{1}{2}V(a)+\frac{1}{2}V(b)-\epsilon$. But, why does it hold with the $\lim\sup$ in front? Again, I'm very thankful for your help/patience!
Apr
27
comment reasonable asymptotic elasticity in utility maximization (paper by Kramkov / Schachermayer)
About the first question: What is your definition of bounded in probability? I use the following: a family of r.v. $\mathcal{F}$ is bounded in probability if and only if $\lim_{r\to \infty}\sup_{f\in\mathcal{F}}P(|f|>r)=0$. But what exactly do you mean by "add in a term for free"?
Apr
26
asked reasonable asymptotic elasticity in utility maximization (paper by Kramkov / Schachermayer)
Apr
23
accepted Utility maximisation
Apr
23
comment Utility maximisation
@quasi I think I need only the inclusion, that I not have. Since for a given $V(z,\theta)$ I need to split it up, right? For your decomposition: Why is it true that $x+\frac{x}{x+y}(\theta\bullet S)\ge 0$?
Apr
23
asked Utility maximisation
Apr
12
comment Hedging duality
how can I migrate a question? Btw...thank a lot for your patience. I think we have a different approach in the proof of $X$ being a supermartingale, i.e. different definition for fork-convex. Note, in my notes we never call it "fork-convex".
Apr
11
comment Hedging duality
The reason why I asked about Fork-convexity, is the following question, posted on MSE. In the prove that $X_t$ is supermartingale, they claim this. Maybe you want to answer this too ;) math.stackexchange.com/questions/355702/…
Apr
11
accepted Hedging duality
Apr
11
comment Hedging duality
Btw...I searched the web about a proof of the fork-convexity of $\mathbb{P}$ without success. Do you have a reference, link, pdf etc?
Apr
11
comment Hedging duality
Well I agree that $X$ is $Q^*$ martingale and hence everything works. But I don't understand what you mean with $X$ and $X^{Q^*}$ are equal? But this is not needed. All you need is, (at least I guess), is: you have a supermatingel with $E[X_0]=E[X_T]$ hence it is a martingale.
Apr
11
comment Hedging duality
Thanks for your answer. I know the result that $X_t$ is a supermartingale for every $Q\in\mathbb{P}$. The poof is not straightforward, not at all. At least the one I know. This just as a personal side remark :) I have one question: 1. Why are the two processes $X$ and $H$ are equal?
Apr
10
revised Hedging duality
edited body
Apr
10
comment Hedging duality
@Freddy No, not at all :)
Apr
10
asked Hedging duality