Q:

(Vim key mapping) Is that possible to map '<' or '>' in Vim?

I want to add such key mapping like:
nmap <C->> <C-W>+
nmap <C-<> <C-W>-

but it seems doesn't work. 
Is there any problem with the syntax? I'm wondering that the '>' or '<' could be used just like the normal characters.

A:

It has nothing to do with the syntax, but with one of the following:

Terminal may send <C-<> as just <.
If there is a way to get <C-<> from a terminal, vim does not know about it.
If you are in GUI the representation of <C- combos cannot possibly handle <C-<> because the only keys it knows are from <C-@> (ctrl+0x40) to <C-_> (ctrl+0x5F) because only these combos can be possibly translated to the ASCII control characters (ones with 0x00—0x1F codes). < and > both fall out of this range.

And addition: use nnoremap, not nmap. You don’t need remapping here.

A:

Due to the way that the keyboard input is handled internally, this unfortunately isn't possible today, even in GVIM. This is a known pain point, and the subject of various discussions on vim_dev and the #vim IRC channel.
Some people (foremost Paul LeoNerd Evans) want to fix that (even for console Vim in terminals that support this), and have floated various proposals, cp. http://groups.google.com/group/vim_dev/browse_thread/thread/626e83fa4588b32a/bfbcb22f37a8a1f8
But as of today, no patches or volunteers have yet come forward, though many have expressed a desire to have this in a future Vim 8 major release.

