The definition of a connected graph states that:
A graph $G$ is called connected provided for each pair $a,b$ with $a\neq b$ of vertices $\exists$ a walk joining a and b.(equivalently a chain joining $a$ and $b$)...
What does the definition mean by (equivalently a chain joining $a$ and $b$) .Please help...
A chain is simply a sequence of edges, forming a path.
A path is a walk without repeated vertices.
If there is a walk between two vertices a and b, there is also a path connecting them.