Equivalence of Definitions of Locally Connected Space/Definition 3 implies Definition 1

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Theorem

Let $T = \struct {S, \tau}$ be a topological space.

Let $T$ have a basis $\BB$ consisting of connected sets in $T$.


Then each point $x$ of $T$ has a local basis $\BB_x$ consisting entirely of connected sets in $T$.


Proof

For each $x \in S$ we define:

$\BB_x = \set {B \in \BB: x \in B}$

From Basis induces Local Basis, $\BB_x$ is a local basis.

As each element of $\BB_x$ is also an element of $\BB$, it follows that $\BB_x$ is also formed of connected sets.

Thus, for each point $x \in S$, there is a local basis which consists entirely of connected sets.

$\blacksquare$