TABLE 1:

Notations used in CHEER.

Notation	Definition
${𝓗}_r\triangleq {\left\{\left({\mathbf{x}}_i^r,y_i^r\right)\right\}}_{i=1}^n$; $𝓣\left(y\mid {\mathbf{x}}^r\right)$	rich data; rich model
${𝓗}_p\triangleq {\left\{\left({\mathbf{x}}_i^p,y_i^p\right)\right\}}_{i=1}^m$; $𝓢\left(y\mid {\mathbf{x}}^p\right)$	poor data; poor model
${𝓗}_o\triangleq {\left\{\left({\mathbf{x}}_i^r,{\mathbf{x}}_i^p,y_i\right)\right\}}_{i=1}^k$	paired data
${\mathbf{Q}}_r\triangleq \left[q_r^1\dots q_r^{l_r}\right]\in {ℝ}^{d\times l_r}$	domain-specific features
${\mathbf{A}}_r\left({\mathbf{x}}^r\right)\triangleq \left[a_r^{(1)}\left({\mathbf{x}}^r\right)\dots a_r^{(d)}\left({\mathbf{x}}^r\right)\right]$	feature scoring functions
${\mathbf{O}}_r\triangleq {\mathbf{O}}_r\left({\mathbf{Q}}_r^{\top }{\mathbf{A}}_r\left({\mathbf{x}}^r\right)\right)$	feature aggregation component