Talk:Green's identities

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[edit] Proofs?

Probably would be worth adding, at least from the divergence theorem Eraserhead1 12:15, 25 May 2007 (UTC)

[edit] Direction of contour integral

I was just reading this page to try and work out which direction the contour integral has to be taken with and the page does not tell me. I think this should be made clear. —Preceding unsigned comment added by Kiwimhm (talk • contribs) 07:02, 10 November 2007 (UTC)

First, the integral over the boundary need not be a contour. If U is in 3D, its boundary would be a surface.

About the orientation of the contour, the standard way is I think that you take the outer normal to the boundary, then rotate it 90 degree counterclockwise. That will show which direction the contour goes. So, if your domain is a disk, the contour will go counterclockwise, but if the domain is an annulus, the outer contour will go counterclockwise but the inner contour will be clockwise. At least, that's how I remember it. Oleg Alexandrov (talk) 02:33, 16 April 2008 (UTC)

[edit] Psi

The third Green's identity says "if psi is twice continuously differentiable" but psi is not mentioned previously in that section. Overall, this page looks like it needs expansion, correction and tidying up. AstroDave (talk) 19:09, 15 April 2008 (UTC)

Psi is mentinoned right below in the text. It is just an arbitrary smooth function, for which the third Green's identity holds. Oleg Alexandrov (talk) 02:26, 16 April 2008 (UTC)