Timeline for "Mathematics talk" for five year olds
Current License: CC BY-SA 3.0
13 events
| when toggle format | what | by | license | comment | |
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| Jun 15, 2020 at 7:27 | history | edited | CommunityBot |
Commonmark migration
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| Jun 2, 2017 at 13:08 | comment | added | Gerry Myerson | @Ronnie, they are called deltahedra, and there are eight of them. en.wikipedia.org/wiki/Deltahedron | |
| Sep 3, 2016 at 14:00 | history | edited | Martin Sleziak | CC BY-SA 3.0 |
corrected minor typo + added Google Books link
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| Jun 6, 2013 at 11:17 | comment | added | Ronnie Brown | @Douglas: I agree about the advantages of polydron. A good test is: how many essentially different convex solids (hollow of course!) can you make from the triangles? This gets over ideas of "convex", "essentially different", and the answer is not so well known. (My memory is 7. Anyone with a web reference? ) I once completely baffled first year undergraduates by giving them this test! They are used to thinking of maths in other ways, I fear. This was in a varuation of the course pages.bangor.ac.uk/~mas010/ideasev.htm | |
| Oct 12, 2012 at 6:29 | comment | added | Douglas Zare | My guess is that "four-space" was a misquotation or misstatement. I don't think there is a comfortable way to immerse a hyperbolic quilt, and I think they probably just made an embedded piece. | |
| Oct 12, 2012 at 2:02 | comment | added | Steven Gubkin | @sridhar - just a guess, but maybe they intersect themselves after you add enough triangles, and so to avoid this intersection you think of them as 3 dimensional projections of 4 dimensional objects? | |
| Oct 3, 2012 at 17:06 | comment | added | Sridhar Ramesh | Naive question: what is the sense in which these final tessellations live in FOUR-space? | |
| Oct 2, 2012 at 21:39 | comment | added | Douglas Zare | I did try that once, but I don't recall the answer. I'll have to find them to check. | |
| Oct 2, 2012 at 19:43 | comment | added | Steven Gubkin | I would guess that physical constraints would prevent you from using Polydrons from adding too many triangles around a central vertex. Certainly 7 would be doable. Have you tried seeing how high you can go? | |
| Oct 2, 2012 at 16:15 | vote | accept | Predrag Punosevac | ||
| Oct 2, 2012 at 4:02 | comment | added | Douglas Zare | There are bright plastic polygons which snap together and hinge at the edges called Polydrons. I use them myself, but I think they are designed to appeal to children, too. They are a little expensive for toys but I think the intuition you can gain from playing with them is hard to acquire otherwise. | |
| Oct 2, 2012 at 0:54 | comment | added | Steven Gubkin | This is really great! Never thought about modeling hyperbolic space this way... | |
| Oct 1, 2012 at 23:06 | history | answered | Todd Trimble | CC BY-SA 3.0 |