| − | \mathcal{L}_{Skip-gram} = log\sigma(\mathbf{v}^\top_{w_o} \mathbf{v}_{w_t}) + \sum^{k}_{i=1}log\sigma(-\mathbf{v}^\top_{w'_{o_i}} \mathbf{v}_{w_t}) | + | \mathcal{L}_{Skip-gram} = \log\sigma(\mathbf{v}^\top_{w_o} \mathbf{v}_{w_t}) + \sum^{k}_{i=1}\log\sigma(-\mathbf{v}^\top_{w'_{o_i}} \mathbf{v}_{w_t}) |