jofisher

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16 Questions

views newest activity votes

5

15

votes

2

answers

479

views

If $G$ is biconnected and $\delta(G) \geq 3 \Rightarrow \exists v: G-v$ is also biconnected.

graph-theory

mar 13 at 13:48 Martin Sleziak 20.3k

1

9

votes

2

answers

462

views

Suppose $a \in \mathbb{R}$, and $\exists n \in \mathbb{N}$, that $a^n \in \mathbb{Q}$, and $(a + 1)^n \in \mathbb{Q}$

number-theory algebraic-number-theory complex-numbers

dec 22 '11 at 16:13 Community♦ 1

3

5

votes

1

answer

163

views

Let graph $G = (V, E)$ $\Rightarrow$ $\alpha(G) \ge \frac{{|V|}^{2}}{2 \times (|E| + |V|)}$

homework graph-theory

oct 12 at 11:47 Douglas S. Stones 11.2k

2

5

votes

1

answer

152

views

Every automorphism of a tree with an odd number of vertices has a fixed point

graph-theory trees

oct 7 at 21:11 Ted 7,529

3

votes

2

answers

142

views

Why for number of leaves in a tree (all types of trees) is it true

combinatorics graph-theory trees

sep 29 at 8:14 Martin Sleziak 20.3k

3

2

votes

0

answers

142

views

Questions about Hamiltonian Graph

graph-theory

nov 30 at 1:08 jofisher 141

1

2

votes

1

answer

204

views

How to prove the non-obvious properties for Critical graph?

graph-theory

oct 7 at 13:59 jofisher 141

2

2

votes

1

answer

78

views

$G$ is bipartite $\Leftrightarrow$ $\forall H$, $H$ is sub-graph of $G$ $\Rightarrow$ $\alpha(H) \ge \frac{|H|}{2}$

homework graph-theory

oct 4 at 22:42 EuYu 15.3k

2

2

votes

1

answer

50

views

Let $G = (V, E)$ is a connected graph $\Rightarrow$ $\alpha(G) \le \frac{|E|}{\delta}$

graph-theory

oct 4 at 17:14 EuYu 15.3k

2

votes

2

answers

297

views

Why are $A=\begin{bmatrix} a & b \\ c & d \end{bmatrix}$ and $B=\begin{bmatrix} 0 & 1 \\ -\det(A) & \operatorname{tr}(A) \end{bmatrix}$ similar?

linear-algebra matrices

dec 26 '11 at 9:19 Pierre-Yves Gaillard 8,477

1

1

vote

1

answer

124

views

Why graph $G = (V, E)$ is elementary cycle?

homework graph-theory

jan 12 at 2:31 Community♦ 1

2

1

vote

2

answers

79

views

For which $n$ is the graph $C^2_n$ planar?

graph-theory

oct 26 at 19:51 Michael Biro 1,493

2

1

vote

1

answer

35

views

If $G$ is a tree and $\forall v_1, v_2 : dist(v_1, v_2)$ is even, where $v_1, v_2-$ are leaves $\Rightarrow \exists!$ a maximal independent set.

homework graph-theory trees

oct 26 at 6:20 Hagen von Eitzen 42.4k

1

1

vote

0

answers

44

views

Every ${K}_{1, 3}$-free connected graph of even order has a perfect matching.

homework graph-theory

oct 16 at 20:26 kahen 8,064

1

1

vote

1

answer

166

views

How to prove the next properties for Critical graph?

graph-theory

oct 8 at 10:12 jofisher 141

1

0

votes

1

answer

33

views

In three-connected graph $G = (V, E)$ $\forall a,b,c \in V \Rightarrow a,b,c \in C$, where $C$ is simple cycle.

homework graph-theory

oct 16 at 22:13 Luke Mathieson 807

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