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BP1237 Connected fractal vs. disconnected fractal.
(edit; present; nest [left/right]; search; history)
CROSSREFS

Adjacent-numbered pages:
BP1232 BP1233 BP1234 BP1235 BP1236  *  BP1238 BP1239 BP1240 BP1241 BP1242

KEYWORD

notso, perfect, infinitedetail

CONCEPT connected_component (info | search),
fractal (info | search)

WORLD

fractal_self_tile [smaller | same | bigger]
zoom in left (connected_fractal_self_tile)

AUTHOR

Jago Collins

BP1238 Fractal with hole vs. fractal with no hole (simply connected).
(edit; present; nest [left/right]; search; history)
CROSSREFS

Adjacent-numbered pages:
BP1233 BP1234 BP1235 BP1236 BP1237  *  BP1239 BP1240 BP1241 BP1242 BP1243

KEYWORD

notso, perfect, infinitedetail

CONCEPT closed_open (info | search),
existence (info | search),
fractal (info | search),
hole (info | search),
loop (info | search)

WORLD

connected_fractal_self_tile [smaller | same | bigger]

AUTHOR

Aaron David Fairbanks

BP1239 Fractal topologically closed (each white point has a neighborhood of pure white surrounding it) vs. not
(edit; present; nest [left/right]; search; history)
COMMENTS

It isn't possible to unambiguously communicate whether or not a few specific points are missing.

CROSSREFS

Adjacent-numbered pages:
BP1234 BP1235 BP1236 BP1237 BP1238  *  BP1240 BP1241 BP1242 BP1243 BP1244

KEYWORD

notso, perfect, infinitedetail

CONCEPT fractal (info | search)

AUTHOR

Aaron David Fairbanks

BP1241 Any point contained in (arbitrarily) smaller version of self vs. not so.
(edit; present; nest [left/right]; search; history)
COMMENTS

Note if any point is contained in some smaller version of the whole, then any point is contained in arbitrarily smaller versions of the whole.


It isn't possible to unambiguously communicate in a picture whether or not a few specific points are included in the fractal. The pictures are interpreted as what is intuitively simplest. To make matters less ambiguous, all the fractals here contain all points arbitrarily close to points in them. (They are topologically closed. See also BP1239.)


The left hand side of this is a stronger condition than the left hand side of BP1116.

CROSSREFS

Adjacent-numbered pages:
BP1236 BP1237 BP1238 BP1239 BP1240  *  BP1242 BP1243 BP1244 BP1245 BP1246

KEYWORD

notso, perfect, infinitedetail

CONCEPT fractal (info | search),
recursion (info | search),
self-reference (info | search)

WORLD

connected_fractal [smaller | same | bigger]

AUTHOR

Aaron David Fairbanks

BP1248 No straight path passes from a white region to a grey one, then to white again (without hitting black) vs. such a path exists.
(edit; present; nest [left/right]; search; history)
CROSSREFS

Any small amount of convexity along the grey border will cause an example to fit right.

Adjacent-numbered pages:
BP1243 BP1244 BP1245 BP1246 BP1247  *  BP1249 BP1250 BP1251 BP1252 BP1253

KEYWORD

precise, allsorted, unwordable, notso, perfect

CONCEPT imagined_line_or_curve (info | search)

WORLD

[smaller | same | bigger]
zoom in left

AUTHOR

Leo Crabbe

BP1249 Any straight path will hit a black region vs. not so.
(edit; present; nest [left/right]; search; history)
REFERENCE

https://en.wikipedia.org/wiki/Opaque_set

CROSSREFS

Adjacent-numbered pages:
BP1244 BP1245 BP1246 BP1247 BP1248  *  BP1250 BP1251 BP1252 BP1253 BP1254

KEYWORD

notso, blackwhite, right-null, perfect, bordercontent

CONCEPT imagined_line_or_curve (info | search)

AUTHOR

Leo Crabbe

BP1261 Exactly one connected white region for each possible way shapes can overlap vs. not so.
(edit; present; nest [left/right]; search; history)
COMMENTS

All left-sorted examples have 2^n distinct white regions (counting the background), where n is the number of shapes in the image.

REFERENCE

https://en.wikipedia.org/wiki/Venn_diagram

CROSSREFS

Similar solution to BP1262, except there overlaps do not have to be unique.

Adjacent-numbered pages:
BP1256 BP1257 BP1258 BP1259 BP1260  *  BP1262 BP1263 BP1264 BP1265 BP1266

KEYWORD

notso, left-narrow, left-null, perfect

CONCEPT exists_one (info | search)

AUTHOR

Leo Crabbe

BP1267 Any two lines intersect, and no three lines share an intersection point vs. not so.
(edit; present; nest [left/right]; search; history)
COMMENTS

Left-sorted examples divide the plane into a maximal amount of disconnected white regions by a given number of "cuts". The number of regions in one of these examples will be the nth value of of the Lazy Caterer sequence ( https://oeis.org/A000124 ), where n is the number of lines.

REFERENCE

https://en.wikipedia.org/wiki/Lazy_caterer%27s_sequence

CROSSREFS

Adjacent-numbered pages:
BP1262 BP1263 BP1264 BP1265 BP1266  *  BP1268 BP1269

KEYWORD

precise, allsorted, notso, perfect

AUTHOR

Leo Crabbe

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