Post

Now also on arxiv arxiv.org/abs/2606.01190

arxiv.orgThe anti-lexicographic SUS-anchor: a near-optimal k=1 sampling schemeIn recent years, there has been a renewed interest in the search for low density minimizer schemes. These schemes take a window of $w$ consecutive $k$-mers, and sample one of them: the smallest under ...

Ragnar {Groot Koerkamp}@curiouscoding.nl

My WABI submission: anti-lexicographic SUS-anchors. For sigma=4, this selection scheme (a k=1 sampling scheme) has density within 1% of the lower bound! The idea: find the smallest* substring that does not have a 2nd occurrence, and sample its start pos. curiouscoding.nl/posts/sus-an...

Adam Phillippy

@aphillippy.bsky.social

3 June

Neat! How did you come up with the "anti-lexicographic" trick?

Ragnar {Groot Koerkamp}

@curiouscoding.nl

Hmmm; it's been a while, but basically all variations were done before: ABBB scheme does 01111 in binary, which can generalize to arbitrary alphabet in 2 ways: ABB which collapses everything, and anti-lex which does not. And the alternating (AZAZAZ) scheme was also done before.

3/6/26, 9:41 pm0 reposts1 like

Ragnar {Groot Koerkamp}

@curiouscoding.nl

3 June

I wouldn't be very surprised if this anti-lex was done before too just not written down (or written down and I'm not aware). In the end the fact that it works so well with the sus-anchor was mostly just luck from playing around. I haven't fully understood yet why it works so well.