let $X=(-\infty, -1) \cup [0,\infty)$, subspace of $\mathbb{R}$. Then is it different from the order topology? Say $(-1/2,1) \cap X =[0,1)$ is open in $X$, but not open in the order topology??
I once questioned it... but still confused
so, [0,1) is not basis for order topology on X?( not open in order topology on X?)
Yes $[0,1)$ is not a basis for the order topology because a basis $\mathcal{B}$ for the order topology should contain all sets of the following types:
1) All open intervals $(a,b)$
2) Intervals of the form $[a_1,b)$
3) Intervals of the form $(a,b_0]$.
Then only we call the set a basis.