Jump to content

Talk:Dym equation

Page contents not supported in other languages.
From Wikipedia, the free encyclopedia

Alternative formulation?

[edit]

The Dym equation

appears to be written in many places as

and it is claimed for example in

  • Olver, Peter J. (1993). Applications of Lie groups to differential equations, 2nd ed. New York, NY; London: Springer-Verlag. ISBN 0387940073.

that the two forms are equivalent. Can an expert confirm that? Oleg Alexandrov (talk) 04:10, 26 January 2007 (UTC)[reply]

Well, Peter Olver is an überexpert so his word is law, but for your edification: Substitute in to get and do the differentiation with respect to t to get . Finally, do some rescaling to get rid of the factor ; for instance, set . Any mistakes in my computations are left as an exercise for the reader. -- Jitse Niesen (talk) 08:40, 26 January 2007 (UTC)[reply]
Thanks! Frankly I was not expecting an answer to the above, it was more of a note to myself. (but big brother Jitse is watching. :)
I added the alternative formulation in the article (that one, is actually used much more often from what I saw in my google books search). If you have more to add to the article, you are more than welcome to. Oleg Alexandrov (talk) 16:47, 26 January 2007 (UTC)[reply]

Harry-Dym equation

[edit]

Is this the same thing as the Harry-Dym equation, or is that something else? 67.198.37.16 (talk) 22:48, 16 September 2020 (UTC)[reply]