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Oct
24
comment Mathematica in Action (Wagon) — code to generate a great circle is giving error
No, I do not. I worked a bit on that result I mentioned about half spheres but did not publish it. I Streinu at Smith College (CS) has a paper with an equivalent version of the same problem. That is mentioned in my book. That paper is S. Felsner, F. Hurtado, M. Noy, and I. Streinu, Hamiltonicity and colorings of arrangement graphs, Discrete Applied Mathematics 154 (2006) 2470-2483. And Joe O'Rourke has included this problem on a list of his of important open problems in geometry.
Oct
23
comment Mathematica in Action (Wagon) — code to generate a great circle is giving error
The conjecture that all those great circle graphs are 3-colorable is now a quite famous conjecture. It is equivalent to some other nice problems. The only partial result I know is a proof I worked out that one can always 3-color the northern hemisphere together with the equator (assumed to be one of the great circles).
Aug
30
awarded  Yearling
May
16
comment Incorporating photos into a Mathematica-made web page
Magnification is default. The image cells look like Cell[BoxData[GraphicsBox[TagBox[RasterBox[CompressedData[" 1:eJx I have tried 2 ways of getting the jpegs into the nb. Main method is to use PhotoShop to resize the image to something suitable for the web, and then copy into M. This past week I used Import["image file"] which places it into M. This gives more control, and I can use things like ImageResize. But the problems all seem to arise from Export to html file, which acts in mysterious ways.
May
16
comment Incorporating photos into a Mathematica-made web page
Re. PNG: Yes I had tried that an hour ago and indeed it is creating larger image files, and the overall result is better. Rasterizing each of the many images in the file? Well I will try one as a test to see if that helps. But PNG seems to be a step in the right direction. A little frustrating though since there ought to be a way to get a JPG at appropriate size.
May
16
comment Incorporating photos into a Mathematica-made web page
I also tried the "ImageEncoding"->"Lossless" option. No progress.
May
16
comment Incorporating photos into a Mathematica-made web page
Thanks. It sounds like just the thing....but it failed. I used: Export[outputstring, Import[inputstring], "Notebook", "ConvertClosed" -> "LinkedPage", "GraphicsOutput" -> {"JPEG", "CompressionLevel" -> 0}] But no change. It turned the source image of size about 6 mb to a jpeg have size 91 kb. So the compression is 65 times, which is of course a big problem.
May
16
awarded  Student
May
16
asked Incorporating photos into a Mathematica-made web page
Mar
15
awarded  Nice Answer
Apr
12
awarded  Good Answer
Jan
26
awarded  Yearling
Jul
13
awarded  Editor
Jul
13
revised Colorize and the Four-Color Theorem
added phrase that it is unsolved whether 4-coloring a planar graph is polynomial time or not.
Jul
12
comment Colorize and the Four-Color Theorem
Note sure how to post art on this site. Here is a pdf with some diagrams illustrating my points. <<stanwagon.com/public/StackExchangeNotes.pdf >>
Jul
11
answered Colorize and the Four-Color Theorem
Jan
26
awarded  Yearling
Oct
4
awarded  Nice Answer
Oct
4
awarded  Teacher
Jan
27
comment Updating Wagon's FindAllCrossings2D[] function
Not on hand. But this function is used many many times in the VisualDSolve project to find equilibrium points for two autonomous DEs and I must have found some difficult examples there. Now, it is possible as Mathematica changes internally that some of the problems disappear. Let me mention that this function was able to solve one of the "100 Digit Challenge" problems in optimizing a complicated function of 2 vbles by finding all of the critical points in the region, and there were well over 2000 of them.