User Louis

9 votes

Proof that $\sum\limits_{i=1}^k \log(i)$ belongs to $O(k)$

answered Dec 22, 2011 at 11:07

7 votes

Accepted

Bijective proof? Examples?

answered Dec 22, 2011 at 10:59

7 votes

Probability of 3 people in a room of 30 having the same birthday

answered Jan 28, 2017 at 1:27

6 votes

Degree of vertices in planar graph

answered Feb 1, 2012 at 19:00

5 votes

Accepted

Diameter of a graph when removing a non-cut edge

answered Dec 23, 2011 at 14:40

5 votes

Accepted

How to prove that $\log_2(n!) = \Theta(n\log_2[n])$?

answered Jan 27, 2013 at 16:52

4 votes

A property of circles

answered Mar 22, 2012 at 9:55

4 votes

Accepted

Proving the Existence of Triangle by Induction

answered Feb 19, 2013 at 15:39

3 votes

Interesting inequalities that can be derived from Cauchy-Schwarz

answered Feb 19, 2018 at 12:26

3 votes

Combinatorial interpretation of sum of squares, cubes

answered Oct 5, 2017 at 11:00

2 votes

Difficulty proving a function exists in both Big $O$and Big $\Omega$

answered Jan 25, 2012 at 21:36

2 votes

Hypergeometric Random Variable Expectation

answered Aug 19, 2020 at 11:22

2 votes

Regular Language

answered Mar 20, 2012 at 10:35

2 votes

Prove that a simple graph with $2n$ vertices without triangles has at most $n^2$ lines.

answered Feb 19, 2013 at 16:26

2 votes

Intuition/explanation of totally disconnected sets (or subsets of R).

answered Oct 8, 2019 at 15:46

1 vote

Accepted

Show that two parallel lines have the same direction vector from a different definition of parallel lines.

answered Mar 17, 2017 at 14:23

1 vote

What is an intuitive approach to solving $\lim_{n\rightarrow\infty}\biggl(\frac{1}{n^2} + \frac{2}{n^2} + \frac{3}{n^2}+\dots+\frac{n}{n^2}\biggr)$?

answered Dec 6, 2017 at 14:17

1 vote

Accepted

Is my proof acceptable? $\rho(\tau\sigma)\leq min\{\rho(\tau),\rho(\sigma)\}$

answered Feb 20, 2018 at 11:12

1 vote

Accepted

Separator of a Planar Graph

answered Jan 31, 2012 at 22:32

1 vote

Edge coloring $K_{2t}$ graph with $t$ colors so it won't contain monochromatic cycle

answered Jan 1, 2012 at 20:23

1 vote

Bayes theorem in a simple example

answered Dec 21, 2011 at 17:30

1 vote

If a plane is divided by $n$ lines, then it is possible to color the regions formed with only two colors.

answered Mar 20, 2012 at 21:04

1 vote

Accepted

Convex Hull Algorithms

answered Mar 21, 2012 at 13:23

1 vote

Accepted

Finding the intersections of straight lines

answered Mar 24, 2012 at 15:43

1 vote

Graphs: trees, induction proof

answered Feb 6, 2013 at 22:12

0 votes

Genus of cellular embedded graph

answered Mar 23, 2012 at 11:25

0 votes

Sufficient conditions on degrees of vertices for existence of a tree

answered Mar 16, 2012 at 11:26

0 votes

Proximity to an orthonormal basis implies linear independence

answered Oct 8, 2019 at 15:16

0 votes

How many papers do you expect to hand in before you receive each possible grade at least once?

answered Mar 1, 2013 at 13:47

Stack Exchange Network

29 Answers

Proof that $\sum\limits_{i=1}^k \log(i)$ belongs to $O(k)$

Bijective proof? Examples?

Probability of 3 people in a room of 30 having the same birthday

Degree of vertices in planar graph

Diameter of a graph when removing a non-cut edge

How to prove that $\log_2(n!) = \Theta(n\log_2[n])$?

A property of circles

Proving the Existence of Triangle by Induction

Interesting inequalities that can be derived from Cauchy-Schwarz

Combinatorial interpretation of sum of squares, cubes

Difficulty proving a function exists in both Big $O$and Big $\Omega$

Hypergeometric Random Variable Expectation

Regular Language

Prove that a simple graph with $2n$ vertices without triangles has at most $n^2$ lines.

Intuition/explanation of totally disconnected sets (or subsets of R).

Show that two parallel lines have the same direction vector from a different definition of parallel lines.

What is an intuitive approach to solving $\lim_{n\rightarrow\infty}\biggl(\frac{1}{n^2} + \frac{2}{n^2} + \frac{3}{n^2}+\dots+\frac{n}{n^2}\biggr)$?

Is my proof acceptable? $\rho(\tau\sigma)\leq min\{\rho(\tau),\rho(\sigma)\}$

Separator of a Planar Graph

Edge coloring $K_{2t}$ graph with $t$ colors so it won't contain monochromatic cycle

Bayes theorem in a simple example

If a plane is divided by $n$ lines, then it is possible to color the regions formed with only two colors.

Convex Hull Algorithms

Finding the intersections of straight lines

Graphs: trees, induction proof

Genus of cellular embedded graph

Sufficient conditions on degrees of vertices for existence of a tree

Proximity to an orthonormal basis implies linear independence

How many papers do you expect to hand in before you receive each possible grade at least once?