What is an orthonormal basis in general relativity?

[Tony Stark]

What is an orthonormal basis??
How is the scalar product of orthonormal basis in GR--
a.b = η_αβa^αb^β.
Please explain

 

[e.bar.goum]

This is a question you should be googling, not asking here. Read these articles, follow links to words you don't understand, and ask questions based on what you understand/don't understand from them.

http://mathworld.wolfram.com/OrthonormalBasis.html
https://en.wikipedia.org/wiki/Orthonormal_basis

 

[Nugatory]

And if ever there was a thread in which what e.bar.goum said should be the last word... This is it.

Thread closed.