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hallstei 2009-06-10 12:29

Lipschitz constants
 
Hi,

I believe this is the appropriate forum for asking this question, even though it is not homework per se.

Where do I find comprehensive information about how to (get my computer to) compute the Lipschitz constant for functions f(x,y)?

Cheers

fivemack 2009-06-10 12:49

Isn't it just the maximum of the absolute value of the derivative?

ATH 2009-06-10 14:05

[URL="http://mathworld.wolfram.com/LipschitzFunction.html"]http://mathworld.wolfram.com/LipschitzFunction.html[/URL]

Its probably the constant C so |f(x)-f(y)| <= C * |x-y| for all x,y.

Yes, maximum |f´(x)| should be at least an upper bound for C.

hallstei 2009-06-10 19:26

[QUOTE=ATH;176911][URL="http://mathworld.wolfram.com/LipschitzFunction.html"]http://mathworld.wolfram.com/LipschitzFunction.html[/URL]

Its probably the constant C so |f(x)-f(y)| <= C * |x-y| for all x,y.

Yes, maximum |f´(x)| should be at least an upper bound for C.[/QUOTE]

Thanks, guys!

Was it really that simple!? I assumed the solution was far more complex, and have spent some time googling for really complicated words.

Any pointers to good textbooks that deals with how to automatically approximate maximums and minimums for general functions?

Cheers

flouran 2009-07-02 20:56

[quote=hallstei;176977]
Any pointers to good textbooks that deals with how to automatically approximate maximums and minimums for general functions?
[/quote]
Any Calculus book will do.
Generally, the extrema of a function g(x) occur when g'(x) changes sign (+ to - for maximum and - to + for minimum) which may take place when g'(x) = 0 or is undefined.


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