Can white mate black?
i'm pretty sure black can mate white
I think white will always be able to block with the rook?
http://www.shredderchess.com/online-chess/online-databases/endgame-database.html
This is a 6-man database, all positions with 6 pieces (including the king, so 4 pieces other than kings) is solved, and you can see how many moves it will be mate in, or if it's a draw with perfect play (except King vs 4 pieces+king, since the answer is retty obvious)
The position is always drawn, except if white has trapped the black king inside a corner with the SAME colour as the bishop:
EDIT: See Viktor's post, he beat me by a minute.
The optimal defense is to put the K in the bishop's "wrong" corner and shuttle the bishop back and forth inbetween the squares adjacent to the king. White can never get the Black K out of this corner, he can only stalemate.
In the given position White can't prevent this defense. You could set up positions with the inferior K trapped on the edge of the board, or with the K in the "right" corner, where the R can win - but not here.
Yep, not a forced mate.
K+R vs K+N does not win either, even if the defense is a bit trickier - I learnt it the hard way playing against a computer a few years ago.
The side with the rook against the minor piece can even have a pawn sometimes, some positions remain drawn. But then the defense becomes incredibly harder !