[ghostwreck]

If you like the idea of solving problems using extra dimensions, Diaspora [1] takes the idea in some really interesting directions. Just be prepared to fight through a few sections of intense Riemannian geometry to bring you into that world.

[1]: https://en.wikipedia.org/wiki/Diaspora_(novel)

[mirimir]

This is probably my favorite novel by Greg Egan. Most of its central characters are AIs.