Let $X$ be a GO-space with the topology $\tau$ and $\lambda$ be the usual open interval topology on $X$. Put $$ R= \{x\in X: [x, \rightarrow) \in \tau\setminus \lambda \} \text{ and } L= \{x\in X: (\leftarrow,x] \in \tau\setminus \lambda \}. $$ Define $X^* \subset X\times \mathbb{Z}$ as follows: $$X^*=(X\times \{0\}) \cup (R \times \{k \in \mathbb{Z}: k<0\})\cup (L \times \{k \in \mathbb{Z}: k>0\}).$$ Let $X^*$ have the open interval topology generated by the lexicographical order. Then $f: X \rightarrow X^*$ defined by $f(x)=\langle x, 0\rangle$ is an order-preserving homeomorphism from $X$ onto the closed subspace $X\times \{0\}$ of $X^*$. So the space $X^*$ is a closed linearly ordered extension of $X$.
My questions are as follows: 1. Let $\{a_n=\langle x_n, k_n\rangle\}$ be a sequence of $X^*$ and let the sequence $\{x_n\} \subset X$ be convergent to $x \in X$. Does $\{a_n\}$ converge to the point $\langle x, 0\rangle$ of $X^*$?
- Suppose that $X$ is first countable. Is also $X^*$ first countable?