User contributions for Gispzjz

16 March 2025

• 15:0215:02, 16 March 2025 diff hist +2 组合数学 (Spring 2025)/Problem Set 1 →Problem 4
• 15:0115:01, 16 March 2025 diff hist +1 组合数学 (Spring 2025)/Problem Set 1 →Problem 4
• 14:5914:59, 16 March 2025 diff hist +172 组合数学 (Spring 2025)/Problem Set 1 No edit summary
• 14:5614:56, 16 March 2025 diff hist +214 组合数学 (Spring 2025)/Problem Set 1 No edit summary
• 14:5314:53, 16 March 2025 diff hist +1,419 N 组合数学 (Spring 2025)/Problem Set 1 Created page with "== Problem 1 == Fix positive integers <math>n</math> and <math>k</math>. Let <math>S</math> be a set with <math>|S|=n</math>. Find the numbers of <math>k</math>-tuples <math>(T_1,T_2,\dots,T_k)</math> of subsets <math>T_i</math> of <math>S</math> subject to each of the following conditions separately. Briefly explain your answer. * <math>T_1\subseteq T_2\subseteq \cdots \subseteq T_k.</math> * The <math> T_i</math>s are pairwise disjoint. * <math> T_1\cup T_2\cup \cdots..."
• 14:5314:53, 16 March 2025 diff hist +61 组合数学 (Spring 2025) →Assignments

18 February 2025

• 10:0110:01, 18 February 2025 diff hist +6 组合数学 (Spring 2025) →Course info
• 09:2909:29, 18 February 2025 diff hist 0 组合数学 (Spring 2025) No edit summary
• 09:2809:28, 18 February 2025 diff hist +1,438 N 组合数学 (Spring 2025)/Course materials Created page with "== Textbooks == {|border="2" cellspacing="4" cellpadding="3" rules="all" style="margin:1em 1em 1em 0; border:solid 1px #AAAAAA; border-collapse:collapse;empty-cells:show;" |border|100px |width="100%"| :J. H. van Lint and R. M. Wilson. ''A course in Combinatorics, 2nd Edition.'' Cambridge University Press, 2001. |- |border|100px|| :S. Jukna. ''Extremal Combinatorics: With Applications in Computer Science, 2nd Edition..." current
• 09:2809:28, 18 February 2025 diff hist 0 组合数学 (Spring 2025) →Course materials
• 09:2609:26, 18 February 2025 diff hist −2 组合数学 (Spring 2025) No edit summary
• 09:2509:25, 18 February 2025 diff hist −3 组合数学 (Spring 2025) →Course info
• 09:2509:25, 18 February 2025 diff hist +1,618 组合数学 (Spring 2025) No edit summary
• 09:2309:23, 18 February 2025 diff hist +39,712 N 组合数学 (Spring 2025)/Basic enumeration Created page with "== Basic Enumeration == The three basic rules for enumeration are: *'''The sum rule''': for any '''''disjoint''''' finite sets <math>S</math> and <math>T</math>, the cardinality of the union <math>|S\cup T|=|S|+|T|</math>. *'''The product rule''': for any finite sets <math>S</math> and <math>T</math>, the cardinality of the Cartesian product <math>|S\times T|=|S|\cdot|T|</math>. *'''The bijection rule''': if there exists a bijection between finite sets <math>S</math> a..." current
• 09:2309:23, 18 February 2025 diff hist +2 组合数学 (Spring 2025) →Lecture Notes
• 09:2109:21, 18 February 2025 diff hist +39,712 N 组合数学 (Fall 2025)/Basic enumeration Created page with "== Basic Enumeration == The three basic rules for enumeration are: *'''The sum rule''': for any '''''disjoint''''' finite sets <math>S</math> and <math>T</math>, the cardinality of the union <math>|S\cup T|=|S|+|T|</math>. *'''The product rule''': for any finite sets <math>S</math> and <math>T</math>, the cardinality of the Cartesian product <math>|S\times T|=|S|\cdot|T|</math>. *'''The bijection rule''': if there exists a bijection between finite sets <math>S</math> a..." current
• 09:2109:21, 18 February 2025 diff hist +2 组合数学 (Spring 2025) →Lecture Notes
• 09:2109:21, 18 February 2025 diff hist +80 组合数学 (Spring 2025) →Lecture Notes
• 09:2009:20, 18 February 2025 diff hist −118 组合数学 (Spring 2025) →Lecture Notes Tag: Visual edit
• 09:1909:19, 18 February 2025 diff hist −1 组合数学 (Spring 2025) →Lecture Notes
• 09:1809:18, 18 February 2025 diff hist +8,827 N 组合数学 (Spring 2025) Created page with " This is the webpage for the ''Combinatorics'' class of Spring 2024. Students who take this class should check this page periodically for content updates and new announcements. = Announcement = = Course info = * '''Instructor ''': 尹一通 ([http://tcs.nju.edu.cn/yinyt/ homepage]) :* '''email''': yinyt@nju.edu.cn :* '''office''': 计算机系 804 * '''Teaching assistant''': ** [https://lhy-gispzjz.github.io/ 刘弘洋] ([mailto:liuhongyang@smail.nju.edu.cn liuhongy..." Tag: Visual edit

12 June 2024

• 13:1713:17, 12 June 2024 diff hist 0 组合数学 (Spring 2024) →Announcement
• 13:1613:16, 12 June 2024 diff hist +36 组合数学 (Spring 2024) →Announcement
• 13:1613:16, 12 June 2024 diff hist +95 组合数学 (Spring 2024) →Announcement

14 May 2024

• 15:5515:55, 14 May 2024 diff hist +1 组合数学 (Spring 2024)/Problem Set 3 →Problem 5
• 15:5515:55, 14 May 2024 diff hist +2,925 N 组合数学 (Spring 2024)/Problem Set 3 Created page with "== Problem 1 == Solve the following two existence problems: * You are given <math>n</math> integers <math>a_1,a_2,\dots,a_n</math>, such that for each <math> 1\leq i\leq n</math> it holds that <math>i-n\leq a_i\leq i-1</math>. Show that there exists a '''nonempty''' subsequence (not necessarily consecutive) of these integers, whose sum is equal to <math> 0 </math>. (Hint: Consider <math> b_i=a_i-i </math>) * You are given two '''multisets''' <math> A </math> and <ma..."
• 15:2415:24, 14 May 2024 diff hist +61 组合数学 (Spring 2024) →Assignments

20 March 2024

• 12:1412:14, 20 March 2024 diff hist +11 组合数学 (Fall 2024)/Problem Set 1 →Problem 4 current
• 12:1412:14, 20 March 2024 diff hist +21 组合数学 (Fall 2024)/Problem Set 1 →Problem 4
• 12:1012:10, 20 March 2024 diff hist +38 组合数学 (Fall 2024)/Problem Set 1 →Problem 4

19 March 2024

• 14:5914:59, 19 March 2024 diff hist +8 组合数学 (Fall 2024)/Problem Set 1 →Problem 5
• 12:4412:44, 19 March 2024 diff hist +28 组合数学 (Fall 2024)/Problem Set 1 →Problem 5
• 12:4312:43, 19 March 2024 diff hist +17 组合数学 (Fall 2024)/Problem Set 1 →Problem 4
• 12:4312:43, 19 March 2024 diff hist +17 组合数学 (Fall 2024)/Problem Set 1 →Problem 3
• 12:4212:42, 19 March 2024 diff hist +6 组合数学 (Fall 2024)/Problem Set 1 →Problem 5
• 12:4212:42, 19 March 2024 diff hist +1,642 N 组合数学 (Fall 2024)/Problem Set 1 Created page with "== Problem 1 == How many <math>n\times m</math> matrices of <math>0</math>'s and <math>1</math>'s are there, such that every row and column contains an even number of <math>1</math>'s? An odd number of <math>1</math>'s? == Problem 2 == * There is a set of <math>2n</math> people: <math>n</math> male and <math>n</math> female. A good party is a set with the same number of male and female. How many possibilities are there to build such a good party? * Try to express the a..."
• 12:4212:42, 19 March 2024 diff hist +53 组合数学 (Spring 2024) →Assignments

8 June 2023

• 14:2614:26, 8 June 2023 diff hist −30 组合数学 (Fall 2023)/Problem Set 4 →Problem 1
• 14:2614:26, 8 June 2023 diff hist +31 组合数学 (Fall 2023)/Problem Set 4 →Problem 1
• 14:2214:22, 8 June 2023 diff hist +136 组合数学 (Fall 2023)/Problem Set 4 →Problem 1
• 14:2114:21, 8 June 2023 diff hist +1 组合数学 (Fall 2023)/Problem Set 4 →Problem 1
• 14:2114:21, 8 June 2023 diff hist +1 组合数学 (Fall 2023)/Problem Set 4 →Problem 5
• 14:2014:20, 8 June 2023 diff hist +4 组合数学 (Fall 2023)/Problem Set 4 →Problem 5
• 14:2014:20, 8 June 2023 diff hist +517 组合数学 (Fall 2023)/Problem Set 4 →Problem 5
• 14:1714:17, 8 June 2023 diff hist +102 组合数学 (Fall 2023)/Problem Set 4 →Problem 5
• 14:1514:15, 8 June 2023 diff hist +1,759 N 组合数学 (Fall 2023)/Problem Set 4 Created page with "== Problem 1 == Prove that * <math>R(4,3)\leq 9</math>. (Hint: Proof by contradiction. Color the edges of <math>K_9</math> in red and blue, and assume that there are no red triangles and no blue <math>4</math>-cliques. Try to determine the number of red and blue edges adjacent to each vertex) * <math>R(4,4)\leq 18</math>. ==Problem 2== We color each non-empty subset of <math>[n]=\{1,2,\ldots,n\}</math> with one of the <math>r</math> colors in <math>[r]</math>. Show tha..."
• 13:2813:28, 8 June 2023 diff hist 0 组合数学 (Spring 2023) →Assignments
• 13:2713:27, 8 June 2023 diff hist +59 组合数学 (Spring 2023) →Assignments

13 April 2023

• 13:2313:23, 13 April 2023 diff hist −2 组合数学 (Fall 2023)/Problem Set 2 →Problem 5
• 13:2213:22, 13 April 2023 diff hist +1 组合数学 (Fall 2023)/Problem Set 2 →Problem 5