\(\text{sim}\left(u,\ v\right)=\frac{u^{T}v}{\left\|u\right\|\left\|v\right\|}={\hat{u}}^{T}\hat{v}\) (2)
\(l_{i,\ j}=-\log\frac{exp(sim(z_{i},\ z_{j})/\tau)}{\sum_{k=1\ (k\neq i)}^{2N}{exp(sim(z_{i},\ z_{k})/\tau)}}\) (3)