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Combinatorics Unsolved Problems

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Home » Olympiad Section » Combinatorics » Combinatorics Unsolved Problems

3680 Topics • Page 1 of 74 • 1, 2, 3, ..., 72, 73, 74 Next

Topics		Author	Replies	Views	Last Post
	Probability of rumor being spread to everyone	mathwizarddude	2	115	Yesterday, at 5:22 pm solyaris
	cardinality of set, gcd Amer. Math. Monthy, 1999	kamil9876	0	52	Fri Nov 20, 2009 11:20 pm kamil9876
	enumeration of euler circuit with certain repeats please, take a look.	Storophanthus	0	44	Fri Nov 20, 2009 8:37 am Storophanthus
	Mod2 and mod3 operations on 1 to 2 vertices Is there a name for it?	kweenie	0	32	Fri Nov 20, 2009 8:02 am kweenie
	Another ABC string question	kweenie	2	78	Fri Nov 20, 2009 7:21 am kweenie
	n-colored graph without triangles China TST 1993, problem 3	orl	2	784	Fri Nov 20, 2009 2:49 am mavropnevma
	Coloring of a checkerboard	apratimdefermat	0	47	Thu Nov 19, 2009 9:27 pm apratimdefermat
	binary number and multiple of 3 binary number, multiple of 3	alpar	1	131	Thu Nov 19, 2009 3:50 pm pleurestique
	cube is cut into finite number of smaller cubes	yzymat	4	112	Thu Nov 19, 2009 3:17 pm mavropnevma
	easy	zaya_yc	1	87	Wed Nov 18, 2009 6:33 pm pleurestique
	ABC string enumerative combinatorics	hendrata01	1	81	Tue Nov 17, 2009 11:34 pm Talegari
	binary strings	aadil	2	68	Tue Nov 17, 2009 2:06 pm hendrata01
	Bijection Q to Q\{0}	aidan	17	627	Tue Nov 17, 2009 12:10 pm Mathmo
	Express n as a sum of numbers	KDS	1	68	Tue Nov 17, 2009 7:05 am JBL
	There is a blue point not on any red line,or there is a red	4dspace	3	66	Tue Nov 17, 2009 6:25 am 4dspace
	x_1+x_2+...+x_n=1979	KDS	0	57	Tue Nov 17, 2009 4:00 am KDS
	japan 1999	Altunshukurlu	1	96	Sun Nov 15, 2009 10:06 am JBL
	1 and -1 on a 9x9 board	KDS	1	136	Sun Nov 15, 2009 8:43 am spanferkel
	place k knight in n*n chessboard	sarahj	0	70	Fri Nov 13, 2009 1:21 am sarahj
	division of a plane and space	aadil	5	155	Thu Nov 12, 2009 9:47 am JBL
	number of ways to make it divisible by p	sarahj	1	84	Thu Nov 12, 2009 6:23 am x164
	No. Of Quadrilaterals that can be formed ???	UTTARA
	rooks	AndrewTom	3	119	Wed Nov 11, 2009 5:30 pm pleurestique
	Sum of proper divisors Argentina MO 2009	uglysolutions	7	213	Wed Nov 11, 2009 11:35 am atomicwedgie
	Teachers and Subjects	Rijul saini	1	93	Tue Nov 10, 2009 8:38 am Agr_94_Math
	robot !	mathnice1	0	97	Tue Nov 10, 2009 8:12 am mathnice1
	distances distances	king.of.dragon	6	438	Tue Nov 10, 2009 6:06 am king.of.dragon
	Directed graph with even cycle	Erken	0	80	Tue Nov 10, 2009 4:52 am Erken
	Chessboard question ... Game ...	Altunshukurlu	2	123	Mon Nov 09, 2009 11:00 pm Johan Gunardi
	Really easy "divide the cube in cubes" problem Brazilian Math Olympiad, Problem 4	cyshine	4	461	Sun Nov 08, 2009 7:30 am davicoelhoamorim
	Distance between some 2 points Romania TST 1990	KDS	0	94	Sat Nov 07, 2009 7:21 pm KDS
	A nice identity Romania TST 1991	KDS	0	165	Sat Nov 07, 2009 7:17 pm KDS
	subsequence of a string subsequence of a string	alpar	6	206	Sat Nov 07, 2009 11:59 am alpar
	Permutation Identity	Jumbler	1	157	Fri Nov 06, 2009 4:26 pm darij grinberg
	no. of soulutions	asish2000	1	97	Fri Nov 06, 2009 3:23 am Talegari
	Constructable total orders of a poset May be well known	Talegari	0	105	Thu Nov 05, 2009 4:34 am Talegari
	use pigeonhole priciple(I think	skywalkerJ.L.	8	434	Wed Nov 04, 2009 2:12 pm fedja
	Pigeonhole principle	mahanmath	2	228	Wed Nov 04, 2009 8:29 am mahanmath
	Max	mahanmath	0	106	Wed Nov 04, 2009 8:23 am mahanmath
	Covering square board Covering square board with triminoes	selmanfarisi	0	90	Tue Nov 03, 2009 6:12 am selmanfarisi
	Weakly decreasing young tableau A possible variation of young's tableau?	Talegari	1	80	Tue Nov 03, 2009 5:25 am JBL
	number of good circles is n China TST 1991, problem 3	orl	9	1125	Tue Nov 03, 2009 5:22 am JBL
	Find the smallest positive integer k Polish MO Round 3 2009,problem 2	math10	0	121	Mon Nov 02, 2009 9:02 pm math10
	How many permutations exist with the given condition? INMO 2007 Question 4	Rijul saini	0	109	Mon Nov 02, 2009 4:36 am Rijul saini
	easy, with coins	tg_free	0	83	Mon Nov 02, 2009 3:28 am tg_free
	Sequence	mahanmath	3	185	Sun Nov 01, 2009 10:42 pm ll931110
	Equivalence relation containment	aidan	8	282	Sun Nov 01, 2009 1:09 pm aidan
	cardinality and permutations (CSMO2009/5) China Southeast Mathematical Olympiad 2009, Problem 5	earldbest	5	338	Sun Nov 01, 2009 2:44 am aadil
	\|X\|=\|Y\|=2^k	Allnames	3	265	Sat Oct 31, 2009 10:41 pm 123eeee
	clique slightly generalize IMO	luapsedree	0	142	Sat Oct 31, 2009 12:57 am luapsedree
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3680 Topics • Page 1 of 74 • 1, 2, 3, ..., 72, 73, 74 Next

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