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<p>This may or may not relate to the current threads about mind v
body, perceptual nature of reality, etc that we have been
flogging, but it is a topic I lived in and around for most of my
career and found it both familiar/compelling and a little
disturbing:</p>
<p>The general topic is the non-Reimannian nature of perceptual
color spaces.</p>
<p>The broadly accepted non-Euclidean color spaces described by the
CIE formulations (1931 and 1976) has been widely accepted while
the RGB/CMYK/HSV Euclidean approximations are what most folks use
for pretty good practical reasons (particular the conveniences of
tristimulus/process color specification and synthesis).<br>
</p>
<p>This recent (1 year old) publication work by some LANL folks was
shoved in my face/space recently (as a correlate to the problems
we have been working with on trying to understand the underlying
space of abstract high dimensional (very non-linear) problems such
as ensemble steering/exploration in the World3 model. Our
favored method (of the moment) is a variant of <a
moz-do-not-send="true"
href="https://en.wikipedia.org/wiki/T-distributed_stochastic_neighbor_embedding">tSNE</a><a
moz-do-not-send="true"
href="https://en.wikipedia.org/wiki/T-distributed_stochastic_neighbor_embedding">
</a>which prefers a locally accurate metric over a global one.<br>
</p>
<p>The LANL work on this non-Reimannian color space:<br>
</p>
<blockquote>
<p><a moz-do-not-send="true"
href="https://www.pnas.org/doi/full/10.1073/pnas.2119753119"
class="moz-txt-link-freetext">https://www.pnas.org/doi/full/10.1073/pnas.2119753119</a></p>
</blockquote>
<p>A popular article about that work:<br>
</p>
<blockquote>
<p><a moz-do-not-send="true"
href="https://www.fastcompany.com/90780869/it-could-take-20-more-years-for-scientists-to-truly-understand-color">https://www.fastcompany.com/90780869/it-could-take-20-more-years-for-scientists-to-truly-understand-color<br>
</a></p>
</blockquote>
<p>I'm guessing this (at least) crossed Ed Angel's awareness,
perhaps there are a few others here who care about this level of
detail/abstraction on color/perceptual spaces? Frank is probably
a lot more up on the nuances of (non) Reimannian manifolds than I
ever will be... I don't know if this represents an interesting
example of the utility of such?<br>
</p>
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