### What does the chromatic number of a graph represent?

Chromatic Number is a numerical representation of the order of events in time. It is defined as the fewest number of colours required to colour each vertex in a graph such that no two adjacent vertices share the same colour (Skiena 1990, p. 210), or in other words, the smallest value of that is necessary to produce a k-coloring. (Skiena 1990, p. 210.)

### Is k2 5 a planar function?

The planar [closed] bipartite graph K2,5 is the full bipartite graph.

### What is the total number of edges in a full graph?

Any two vertices may be connected by an edge in a full graph. You may get an advantage by selecting any two vertices on the board. If there are n vertices, there are n pick 2 = (n2)=(n1)/2 edges, which means there are n vertices in total.

### Which of the following paths is a Hamiltonian circuit?

As a graph is traversed, a Hamiltonian circuit is a route that visits each vertex precisely once and then returns to the starting point. As an example, consider the following graph, which is based on the dodecahedron.

### Is k3 a planar function?

The graph K3,3 does not have a planar shape. We have v = 6 and e = 9 in K3,3 as evidence of this. Kuratowski’s Theorem states that a graph is non-planar if and only if it has a subgraph that is homeomorphic to either K5 or K3,3, and that a graph is non-planar otherwise.

### Where do planar graphs come into play?

When a linked graph can be drawn without any edges crossing, the graph is said to be planar. It is by this method that a planar graph is created, which splits the plane into areas known as faces. Drawing two alternative planar graphs with the same number of vertices, edges, and faces should be attempted if feasible.

### What does it need for a graph to be planar?

An edge of a graph G is considered planar if and only if it can be drawn in the plane in such a manner that no two edges contact each other except at a vertex to which they are both incident. A plane drawing of G is the term used to describe such a depiction. Consider the graph K4, which is planar because it can be drawn in the plane without any of the edges crossing.

### What is the purpose of Euler’s formula?

It is one of two key mathematical theorems of Leonhard Euler, and it is known as the Euler’s formula. It has been shown that each polyhedron may be described by a topological invariance (see topology), which can be expressed as a relationship between the number of faces, vertices, and edges. In mathematics, this is written F + V = E + 2, where F is the number of faces, V denotes the number of vertices, and E denotes the number of edges.

### Is k7 a flat surface?

According to Kuratowski’s theorem, K7 is not a planar function. As a result, K7 has a toroidal shape.

### In chemistry, what is meant by non-planarity?

If the hybridization is sp2 or sp, then the atoms in a molecule would be planar if the hybridization is sp2. Please keep in mind that there may be certain exclusions. It is possible to have two C/N atoms with so2 subsidised atoms that are separated by an even number of double bonds and no single bond that are not planar. This criteria must be met in order for a particular chemical to be considered planar.

### Is the cube a planar graph or not?

Yes. A planar graph is a graph that can be represented in the plane (ie – as a 2D figure) with no overlapping edges, which is the most basic definition. First, a “graph” of a cube, drawn in the conventional manner: When drawn in this manner, it is not immediately clear that it is planar – the edges GH and BC cross, for example.