# Combinatorics and Graph Theory

## 1512 Submissions

[3] **viXra:1512.0343 [pdf]**
*submitted on 2015-12-17 01:55:47*

### Removing Magic from the Normal Distribution and the Stirling and Wallis Formulas.

**Authors:** Mikhail Kovalyov

**Comments:** 8 Pages.

The paper provides an intuitive and very short derivation of the normal distribution and the Stirling and Wallis formulas.

**Category:** Combinatorics and Graph Theory

[2] **viXra:1512.0322 [pdf]**
*replaced on 2015-12-21 02:59:29*

### Isomorphism of Graphs using Ordered Adjacency List

**Authors:** Dhananjay P. Mehendale

**Comments:** 8 Pages. Typos corrected. Added two more examples.

In this paper we develop a novel characterization for isomorphism of graphs. The characterization is obtained in terms of ordered adjacency lists to be associated with two given labeled graphs. We show that the two given labeled graphs are isomorphic if and only if their associated ordered adjacency lists can be made identical by applying the action of suitable transpositions on any one of these lists. We discuss in brief the complexity of the algorithm for deciding isomorphism of graphs and show that it is of the order of the cube of number of the number of edges.

**Category:** Combinatorics and Graph Theory

[1] **viXra:1512.0222 [pdf]**
*replaced on 2015-12-09 16:10:09*

### A Prime Number Based Strategy to Label Graphs and Represent Its Structure as a Single Numerical Value

**Authors:** Prashanth R. Rao

**Comments:** 2 Pages.

We present a simple theoretical strategy to represent using a single numerical value “A” called the prime vertex labeling Adjacency value product, all structural information encoded in a graph. This strategy has the potential to allow us to reconstruct the graph in its entirety based on a single number. To do so we assume that we have access to a large list of prime numbers which are infinite in number. This method will allow us to store graph backbone as a numerical value for retrieval and re-use and may also allow development of algorithms that exploit this representation feature as shortcut to address graph isomorphism.

**Category:** Combinatorics and Graph Theory