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Antinumeric commented on The Unknotting Number Is Not Additive   divisbyzero.com/2025/10/0... · Posted by u/JohnHammersley
gcanyon · 2 months ago
But this implies that a simple 1-knot might completely undo itself if you join it to its mirror. Which I assume people have tried, and doesn't work. Likewise with 2's, 3's etc.

It seems intuitively obvious that there is something deeper going on here that makes these two knots work, where (presumably) many others have failed. Or more interestingly to me, maybe there's something special about the technique they use, and it might be possible to use this technique on any/many pairs of knots to reduce the sum of their unknotting numbers.

Antinumeric · 2 months ago
(non-mathematical) Implication doesn't mean certainty, which is where I stand with that. But I would posit that it (mathematically) implies that joining two knots with under to over will never decrease the unknotting number from the sum.
Antinumeric commented on The Unknotting Number Is Not Additive   divisbyzero.com/2025/10/0... · Posted by u/JohnHammersley
deadfoxygrandpa · 2 months ago
you're either lying or you don't understand what you're looking at. theres a reason this conjecture wasnt disproven for almost a hundred years
Antinumeric · 2 months ago
I'm not saying I could have come up with the example. I'm saying looking at the example, and seeing how the two unders are connected togther, and the two overs connected together, makes it obvious that there is more freedom to move the knot around. And that freedom, at least to me, is intuitively connected to the unknotting number.

And that is why the mirror image had to be taken - you need to make sure that when you join it is over to over and under to under.

Antinumeric commented on The Unknotting Number Is Not Additive   divisbyzero.com/2025/10/0... · Posted by u/JohnHammersley
Antinumeric · 2 months ago
This example seems obvious to me - Joining the under to the under, and the over to the over would obviously give more freedom to the knot than the reverse.

u/Antinumeric

KarmaCake day4October 9, 2025View Original