DD: Knots are only possible in three dimensions. That's why space has three dimensions. Particles are knots in the fabric of spacetime. Anti-particles are anti-knots, which self untangle (and release energy) when brought together. -- That did not actually make sense. (And there are plenty of better-sounding reasons why space should be 3D.) First, knot-like objects are possible for k-manifolds embedded within (k+2)-manifolds (the usual case is k=1). Second, "anti-knots" in a string CANNOT annihilate with knots further up same string, which indeed was recently proven allegedly in posts here about "sum" of two knots never equalling the unknot, and anyhow allegedly has been proven many ways by many people. (Er, you could call that the theorem of the "non-existence of forget-me-knots.") But, if you were to postulate our 3-space really is embedded in some 5-space -- then I suppose you could try to postulate particles are the k=3 analogue of knots [call them "3knots"], and you could try to hope the no-cancel theorem is untrue when k=3 despite its truth when k=1. I doubt the latter hope -- Can Mr. Asimov tell us the answer? If indeed 3knots are capable of cancelling and exhibiting interesting group-relations under "summation," that would be very interesting. But I doubt it. Also, I point out that when an electron and positron annihilate, you don't just get nothing. You get two gamma rays (at least most of the time, anyhow). So I think Dyer would need to postulate not "cancellation" but rather a more interesting set of "group relations" among the 3knots. Also, I point out that photons and gravitons can just get generated ad libitum, e.g. from a hot filament. If these truly were altered topologies, wouldn't that be forbidden? Even if photons are their own antiparticles, you'll still have some issues... -- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)