SERVING THE QUANTITATIVE FINANCE COMMUNITY

  • 1
  • 5
  • 6
  • 7
  • 8
  • 9
 
User avatar
quantmeh
Posts: 5974
Joined: April 6th, 2007, 1:39 pm

Brownian motion, does this phrase make sense?

May 10th, 2007, 10:59 pm

QuoteOriginally posted by: crowlogicYup. So, are stock prices turbulent or follow a BM? I think the former.i'm not sure. they seem to show BM-type behavior sometimes. maybe they're like dying sperm cells, i.e. have little character, but not too much to ignore random influences
 
User avatar
crowlogic
Posts: 658
Joined: May 22nd, 2005, 6:47 pm

Brownian motion, does this phrase make sense?

May 10th, 2007, 11:08 pm

QuoteOriginally posted by: jawabeanQuoteOriginally posted by: crowlogicYup. So, are stock prices turbulent or follow a BM? I think the former.i'm not sure. they seem to show BM-type behavior sometimes. maybe they're like dying sperm cells, i.e. have little character, but not too much to ignore random influences Maybe the prices are constantly undergoing phase-transition between the random and deterministic influences.
 
User avatar
propertyrights
Posts: 94
Joined: September 18th, 2005, 10:01 pm

Brownian motion, does this phrase make sense?

May 12th, 2007, 10:35 pm

QuoteOriginally posted by: NIn fact, Black Scholes is never used either (another math orgasm).How do you reconcile your belief with p. 114 of Taleb's Dynamic Hedging or p. 44 of Natenberg's Option Volatility & Pricing? Note: I am not claiming that Black-Scholes is the be-all and end-all of option pricing models. Obviously, we now have SABR, etc. What I'm saying is that Black-Scholes (or variants like Black's model for futures options) has been heavily used by traders in the past and is still used now (SABR can output Black vols that can be fed to a Black pricer to get dollar prices).
 
User avatar
quantmeh
Posts: 5974
Joined: April 6th, 2007, 1:39 pm

Brownian motion, does this phrase make sense?

May 13th, 2007, 12:04 am

QuoteOriginally posted by: propertyrightsQuoteOriginally posted by: NIn fact, Black Scholes is never used either (another math orgasm). What I'm saying is that Black-Scholes (or variants like Black's model for futures options) has been heavily used by traders in the past and is still used now (SABR can output Black vols that can be fed to a Black pricer to get dollar prices).it's used even in accounting standards such as FAS133
 
User avatar
Frashe
Posts: 60
Joined: January 25th, 2006, 5:01 am

Brownian motion, does this phrase make sense?

May 28th, 2007, 6:28 am

What a bloody waste of time it was following this thread. I thought we might get somewhere, but N just refused to say what he was talking about in a manner that others could understand. And it's not because I don't get the maths, physics and all the rest that N was spouting. I do understand, but N's comments weren't even wrong.
 
User avatar
crowlogic
Posts: 658
Joined: May 22nd, 2005, 6:47 pm

Brownian motion, does this phrase make sense?

May 29th, 2007, 11:23 pm

I believe some of the reasons causing the disagreements around "Brownian Motion" are due to the same fundamental reasons leading to different determinations of what "random" is. See ANKS Ch.10 "Processes of Perception and Analysis" p552, "Defining the Notion of Randomness". He discusses the practical and theoretical concerns about the existence of randomness, specifically how you can really really "random looking" data out of cellular automata which passes all known statistical tests but actually has a very small "minimum description length" by iterating 2d grid based CA. If you want to do MC simulation then just making "random" numbers might suffice but its no replacement for the more concrete/combinatorial permutation enumeration viewpoint.
ABOUT WILMOTT

PW by JB

Wilmott.com has been "Serving the Quantitative Finance Community" since 2001. Continued...


Twitter LinkedIn Instagram

JOBS BOARD

JOBS BOARD

Looking for a quant job, risk, algo trading,...? Browse jobs here...


GZIP: On