Lately I've been doing a lot of work related to solving variational problems (in the context of surface theory), and I'm getting really tired of going to local coordinates for everything.
So, I was wondering: does anyone know a good coordinate-free treatment for the calculus of variations? I've heard such literature exists, but I can't say I'm familiar with it.
Any suggested reading you all may have would be much appreciated.
Thanks in advance,
In case anyone else is curious, I've been getting some mileage out of Differential Geometry and the Calculus of Variations by Robert Hermann.
It's not exactly what I was looking for, but it's quite good, and I'm excited to apply some of the techniques in "Part 2" of the book.