Graph-theory I.

A loop in a graph is ...

• A circle

• the edge - the two end-points of which are the same

• no edge incident with the point

• More than one edge between two points

If we draw more than one edge between two points ...

• then it’s a simple graph

• then we have a loop

• we have isolated points because of this

• then we have a multiple edge

V(G) stands for

• set of edges of the graph

• set of vertices of the graph

• number of isolated points

• number of points

E(G) stands for...

• set of edges of a graph

• number of isolated points

• number of points

• set of vertices of a graph

The sum of degrees of the points in every graph is ...

• is an odd number

• Is an even number

• twice the number of edges

• the half of the number of edges

If we draw more than one edge between two points ...

• then it’s a simple graph

• then we have a loop

• we have isolated points because of this

• then we have a multiple edge