From: Richard Carr Subject: Re: Christmas quiz Date: Thu, 23 Dec 1999 05:22:51 -0500 Newsgroups: sci.math Keywords: [missing] On Wed, 22 Dec 1999, Clive Tooth wrote: :Date: Wed, 22 Dec 1999 13:02:00 -0000 :From: Clive Tooth :Newsgroups: sci.math :Subject: Christmas quiz : :During 1999, who said the following, in sci.math? : :1) "(E!x)P(x) can be defined as (Ex){P(x) & (Ay)[P(y)->x=y]}, or :alternatively (Ex)P(x) & (Ay)(Az)[P(y)&P(z)->y=z], where (Ex) means there :exists (at least one) x, (Ay) means for every y, and -> is implication :(if-then). In mathematics this splitting of unique existence into a :uniqueness condition (Ay)(Az)[P(y)&P(z)->y=z] and an existence condition :(Ex)P(x) is common, and people often prove them separately." : :2) "... see Knuth's ..." : :3) "Beats the hell out of me! Well, the first couple cases are easy." : :4) "Hmmm!? This is exercise # 1 in section 8.8 of the text that I am using :for calculus II -- and it was an assigned homework problem." : :5) "In the Reeb foliation, there is one torus leaf, and the other leaves are :topological disks which fill two solid tori. The disks can be taken to be :perpendicular to the core of each solid torus, but bending so that they spin :infinitely about the solid torus in one direction, so that they are close to :flat near the torus. In other words, one can spin the graphs of sec(x)+c :between -pi/2 and pi/2 about the y-axis, then quotient out by a :translational symmetry." : :6) "Let a[m+k]=sum_{j=1}^k[a[m+j-1]^t_j], each t_j>0." : :7) "The easy way out would be to find one of the web pages which display the :figure and write to the authors for more details. Faster (for me anyway) was :to turn to my references on polyhedra..." : :8) "The general solution for g, according to Maple, is g(t) = :1/2*I*k*sqrt(Pi)*sqrt(2)*int(erf(1/2*I*sqrt(2)*(-1+t))*exp(-1/2*(-1+t)^2),t) : -1/2*I*k*Pi*erf(1/2*sqrt(2)*t-1/2*sqrt(2))*erf(1/2*I*sqrt(2)*(-1+t)) :+_C1+_C2*erf(1/2*I*sqrt(2)*(-1+t))" : :And these two posters are closely associated: : :9) "I'm sorry to have to appear rude, but I'm afraid this is bollocks." : :10) "At your age, young men are usually more interested in hairy triangles." : :~ ~ ~ ~ : :If you want to post answers, don't forget that in 1999 we also had the :attempted introduction (and subsequent vanishing without trace) of the :Standard Spoiler... :http://www.deja.com/[ST_rn=ps]/getdoc.xp?AN=465653342&fmt=text : ::-) : :-- :Clive Tooth :http://www.pisquaredoversix.force9.co.uk/ :End of document : Spoilers: 1) Keith Ramsey 2) Lynn Killingbeck 3) Fred Galvin 4) Charles H. Giffen 5) Douglas Zare 6) Leroy Quet 7) Dave Rusin 8) Robert Israel 9) Robin Chapman 10) Pertti Lounesto Useful thing that www.deja.com.