Below are the 20 most recent journal entries recorded in Graphs, designs, numbers, etc.'s LiveJournal:

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Monday, July 13th, 2009
7:15 pm [gaffetheorist]	Transportation Was someone volunteering to come to the airport & pick up the various northerners as our flights arrive? If so, who? (6 Comments |Comment on this)
Sunday, June 14th, 2009
7:42 pm [leachboy]	Hotel Info alexsala and I have investigated using the Holiday Inn Express ATLANTA/SMYRNA-COBB GALLERIA for using for DANGER. I talked to them a while back, and they had a baseball team using all the conference rooms, so the plan is to use this as a place to crash and SPSU for classroom space. (4 Comments |Comment on this)
Sunday, June 7th, 2009
10:57 am [sclark223]	what's the latest?? Can the Planners That Be please post an update, if there is one? All I know is Atlanta area, weekend of July 18. And something about Medieval Times. Do we have more specifics? (1 Comment |Comment on this)
Tuesday, April 7th, 2009
9:14 pm [leachboy]	DANGER 2K9 (or the DANGER went down to Georgia) alexsala called me tonight to talk about DANGER 2K9. The weekend of July 18 has bubbled its way to the top of the possible dates for the meeting. The location will be somewhere in the Metro Atlanta area--most likely at a hotel in Smyrna. sclark223 sugguested that the "banquet" be held at Medieval Times, which I think is in Lawrenceville. It's in the eastern suburbs anyway, near the Mall of Georgia. Give us some feedback if you've got any so that we can more concrete plans made. (3 Comments |Comment on this)
Wednesday, February 18th, 2009
3:46 pm [alexsala]	MAA Who's up? conference (2 Comments |Comment on this)
Wednesday, January 14th, 2009
3:04 pm [gaffetheorist]	Boca '09: March 2--6 The annual question: who all's planning to go? If you're going, when during the week will you be there? I'm currently leaning towards a Monday--Wednesday thing, since it's once again not the same week as my spring break. For accommodations, I'm strongly leaning towards the Boca Raton Plaza where I've stayed the last couple of years (and which has made it on to the conference website!). (4 Comments |Comment on this)
Tuesday, October 7th, 2008
10:00 pm [leachboy]	ICA The ICA now has a website: http://www.theica.org/. When did this happen? (3 Comments |Comment on this)
Tuesday, September 30th, 2008
6:22 pm [leachboy]	Math Wiki This looks interesting, and reminds me of an idea that gaffetheorist and I tossed around a few years back. (Comment on this)
Monday, May 19th, 2008
4:23 pm [sclark223]	tentative DANGER weekend Upcoming DANGER: How does the weekend of July 11 (Friday) thru July 13 (by default, Sunday) suit everyone? Located at Huntingdon College, in Montgomery AL? I'll send email too, to the usual folks who may not blog here. If most folks find this weekend acceptable, then I'll work on specifics - maybe even a website, alexsala! :) (5 Comments |Comment on this)
Friday, April 25th, 2008
9:30 am [trimmje]	Let's Make a Deal v. Deal or No Deal So at knit night last night, a discussion came up of the Monty Hall problem and Deal or No Deal, and whether thousands of people are getting misled about probability every week by Howie Mandel. (Indeed, my knitting group rocks mightily.) Monty Hall asks you to pick one door of three, one has a car behind it, two have goats. Once you have chosen, a non-chosen door is opened to reveal a goat, and despite the un-intuitiveness of it, you still only have a one in three chance of having the car. Deal or No Deal claims at each level that if a person has chosen a case and there are n-1 cases left to be opened and the million dollar prize hasn't appeared yet, there is a one in n chance that the million dollar prize is in the Chosen Case. Open k more cases without revealing a million dollars, and there's now a one in n-k chance for the Chosen Case. My argument is that the difference between these two situations is that in Deal or No Deal the contestant chooses which cases to open, and so there is the possibility of opening case K with a million dollars - eliminating the possibility that the Chosen Case has the million. In Monty Hall, on the other hand, the people opening the door have perfect information, and so when they open a door it's always a goat. This means that a door is opened in any of the three configurations of two goats and a car, but the information given doesn't actually eliminate any possibilities. I'm just wondering if I'm on the right track here or if a new configuration of Monty Hall has gotten past my instincts again. (2 Comments |Comment on this)
Thursday, February 28th, 2008
2:51 pm [leachboy]	bitstrings! The book I'm using to teach combinatorics poses the following problem: How many binary sequences of length 18 are there that start with a run of 1s, that is, a consecutive sequence of at least one 1, then a run of 0s, then a run of 1s, then a run of 0s, and such that one run of 1s has length at least 8. They claim that the answer is 240, but I think that it's 239. What do youse guys think? (3 Comments |Comment on this)
Thursday, January 31st, 2008
5:08 pm [gaffetheorist]	Filling out travel forms My conference plan for the next six months: * Boca, March 5th-7th. (Missing the first two days.) * Mathematical Abundance at Illinois State, April 18th-19th. * MIGHTY 46 at WVU, April 25th-26th. * Istanbul, June 16th-20th. * DANGER '08, apparently in Montgomery, sometime in July? What am I missing? (6 Comments |Comment on this)
Monday, December 10th, 2007
3:33 pm [gaffetheorist]	Fun facts about the golden ratio Let φ denote the Golden Ratio: φ = (1 + √5)/2. Fact #1: Every positive integer can be expressed as a sum of distinct integer powers of φ. Fact #2: If you require that one never employs consecutive powers of φ, then the representation is unique. (I'm pretty sure that this can be refined as follows: take any finite linear combination of powers of φ using positive integer coefficients. Then the resulting number can be expressed uniquely as such a linear combination using only the coefficients 0 and 1.) Question: What positive real numbers share Fact #1 with φ? 1 and 2 both fit the bill, though somewhat boringly in both cases; these represent the extremes, in that any number larger than 2 will perforce miss 2, and for any number smaller than 1 we can just consider the reciprocal instead. Instructive, I think, is that φ satisfies the equation φ = φ0+φ-1; the corresponding equations for 1 and 2 are 1 = 10 and 2 = 20+2-1+2-2+… Do all positive reals that satisfy versions of this (effectively, truncations of the Laurent series for 2) also satisfy Fact #1? Are there other reals that do? Also: can anything interesting be said about the set of numbers that admit these representations in terms of φ? (Comment on this)
Saturday, October 20th, 2007
9:55 am [sclark223]	Curt's Turks? So who is planning to go to Turkey this June? Sule says "everybody" will be there - I have never been sure who she meant by that. (4 Comments |Comment on this)
Saturday, September 22nd, 2007
2:15 am [gaffetheorist]	Steiner systems Anyone know whether a (3,5,50) Steiner system (AKA a 3-(50,5,1) design) exists? And/or where I might find it? The various combinatorial object generators I know of don't seem to do much with block designs. (6 Comments |Comment on this)
Sunday, January 28th, 2007
1:40 pm [alexsala]	Domination 101 I'm scheduled to give a 45 minute talk tomorrow on domination. I've got about 30 minutes of material. HELP! (2 Comments |Comment on this)
11:09 am [alexsala]	Anybody wanna have a DANGER party at the SE-MAA the week after Boca? I'm taking a Jeopardy team to the conference, and I need something to unwind without turning my brain off - I'll buy beer if people will come play math with me. Oh, and I'm looking for a roommate for it too. MAA page (1 Comment |Comment on this)
Saturday, January 27th, 2007
11:59 pm [trimmje]	Boca 2007 again So I'm thinking of going for some portion of the week, contingent on having a reasonably-priced place to stay - i.e., probably a roommate or so who would be willing to share costs.  I'm clean, housetrained, and I've been told my snoring is soft and cute.  Anyone?  Bueller?  (3 Comments |Comment on this)
Wednesday, January 17th, 2007
2:15 pm [leachboy]	Boca 2007 I'm trying to make my plans for Boca this year. I plan to attend the conference Monday through Wednesday, and possibly a few hours on Thursday morning before flying back to the ATL. I'm sharing a room with Abi at the motel formerly known as the Ramadan. What is still up in the air is when I will fly down. Abi's flying down on Saturday, and I might do the same, although if no one else will be there that day, I might opt to wait until Sunday. Are any of the rest of you planning to arrive on Saturday? UPDATE: It's official. I'm flying into Fort Lauderdale on Saturday at 3:50 PM and flying out on Thursday at 12:40 PM. (2 Comments |Comment on this)
Tuesday, October 24th, 2006
3:53 pm [gaffetheorist]	Regular graphs with a given substructure At least the first of these questions has probably been tackled someplace; look familiar to anyone? (1) Let G be a graph with δ(G)<Δ(G); must there exist a regular graph H which contains G as an induced subgraph? Assuming so, find a construction for such an H that minimizes... something. (Vertex degree? Number of vertices? Number of edges? Not sure which is the more interesting question, but you can get different answers.) (2) As above, but now require that H be vertex-transitive. (3) As in (1), but now require that the automorphism group of G extend to the automorphism group of H. (N.B. I mean something stronger than having Aut(G) be a subgroup of Aut(H); every automorphism of G should be extendable to an automorphism of H.) This could also be combined with (2), though it doesn't need to be. Current Music: Sloan (Comment on this)