Does somebody knows how to project a discrete-time quantum walk with a Grover coin on the hypercube onto the line? I was trying to reproduce this paper http://arxiv.org/abs/quant-ph/0210064" [Broken], and I cannot understand how does it manage to do that. I'm posting as an attachment to this post the part of the paper that I cannot solve since latex is not working right now (I hope it doesn't violate any rules of the forum, since it is available in quant-ph). Thanks in advanced!!