{ } — a set

$\{0, 1\}$ is the set that contains exactly zero and one. A raised size after it works like $\mathbb{R}^d$: $\{0, 1\}^{|V|}$ is every vector of length $|V|$ whose entries are each $0$ or $1$. A one-hot vector is one of these.

The $\dots$ inside braces means "continue the obvious pattern": $\{1, 2, \dots, d/2\}$ is every whole number from 1 to $d/2$.