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lift . fmap NE.nonEmpty . (<$> f floor) . (++) . maybe [] NE.toList
gosh I love Haskell

when we're talking about infinite sets (say of real numbers) we use sup and inf instead, and there's a simpler argument: sup S is the least element that's ≥ x for all x ∈ S. if S is empty the second clause is vacuous and so we just get the least element of the extended reals, -∞.

since this seems to annoy people when programming languages do it: there's a good reason to "define" max ∅ := -∞ and min ∅ := ∞—namely, it preserves the monotonicity properties
S ⊂ T ⇒ min S ≥ min T and max S ≤ max T. for these to hold in general we need in particular min ∅ ≥ min {a} = a for all elements a, so min ∅ must be maximal (and similarly max ∅ must be minimal).

"Froh, wie seine Sonnen fliegen / Durch des Himmels prächt'gen Plan, / Laufet, Brüder, eure Bahn, / Freudig, wie ein Held zum Siegen" sure sounds good but I'm not sure I'd actually like to be in a 240m-year orbit around the center of the Milky Way

Finally starting to run into situations where I find myself wanting (the simpler applications of) lenses. Thank goodness for "lens over tea": artyom.me/lens-over-tea-1 (all I actually need for the moment is %~ and .= for conveniently updating records)

I'm interested most seriously in math--analysis more than algebra, learning lately about combinatorial/incidence geometry (e.g. the Erdős distinct-distance problem)--and programming--mostly in Haskell, although I'm curious about C and systems-level things as well. On the amateur plane I like classical music and read haphazardly in the s-f/litfic/poetry space. I try to learn from the example of people who're more knowledgeable or skillful than I am.

is it bad form to mix mutable and immutable records within my data structure, I wonder

Haskell newtypes are not my favorite thing...like, I find myself reaching for the Semigroup/Monoid instance for predicates under conjunction but it's so clunky to use:
newPred = getAll . ((All . somePred . foo) <> (All . otherPred . bar))
when the alternative is
newPred x = (somePred $ foo x) && (otherPred $ bar x)

be the one-eyed king in the land of the blind by skimming academic papers that you see cited in the news

please reprimand me if I ever call something a "tour de force" and appear to mean it

same goes for news articles tbh

"I mentioned politicks. JOHNSON. 'Sir, I'd as soon have a man to break my bones as talk to me of publick affairs, internal or external. I have lived to see things all as bad as they can be.'"

TIL that one Auden poem ("'O where are you going?' said reader to rider / ...") was probably inspired by this folk song: en.wikipedia.org/wiki/Cutty_Wr

Goodreads seems to have jumped aboard the non-chronological timelines train, aaargh

I passed some Jimmy Dean product in the grocery store today and it reminded me of this impeccable Buttercup Festival strip buttercupfestival.com/col12vol

it's cool that the geometry of great circles on the 2-sphere is the same as the geometry of lines in the real projective plane

Samuel Johnson is reminding me a bit of Paul Erdős

"His definition of 𝘕𝘦𝘵𝘸𝘰𝘳𝘬 has been often quoted with sportive malignity, as obscuring a thing in itself very plain."