User talk:Wythagoras/Rado's sigma function/Multi-headed TMs

This is what I think Ikosarakt meant - heads can't refer to content of tape other head is over. Only way of interaction between heads is by having them visit same cell. So when head halts, it is just as we threw it out of machine. LittlePeng9 (talk) 11:59, September 14, 2013 (UTC)