Trivially, in the negative. Without borders, there are 56 edges, which is not a triangular number, so cannot be a full set of dominoes, either including or excluding doubles. -- Mike ----- Original Message ----- From: "Dan Asimov" <dasimov@earthlink.net> To: "math-fun" <math-fun@mailman.xmission.com> Sent: Thursday, September 02, 2010 8:44 PM Subject: Re: [math-fun] domino networks

My standard question: What if instead of using the 4x7 rectangular network, one uses the 4x7 *toral* network? (I.e., the product of a 4-cycle and a 7-cycle.)

Then can the domino question be solved?

--Dan

_____________________________________________________________________ "It don't mean a thing if it ain't got that certain je ne sais quoi." --Peter Schickele

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