Table 1.

The list of symbols.

Symbol	Description	Symbol	Description
	The input spaces of the samples		The raw input of the i-th sample
	The class label spaces of the samples		The class label of the i-th sample
	The domain space of the dataset		The domain label of the i-th sample
	The class space of the dataset	M	The number of classes in the dataset
	The mapped feature representation space of the samples		The mapped feature representation of the i-th sample
K	The number of domains in the dataset		The kernel function
	The d-th domain		The class distribution of the d-th domain
	The class label set of the d-th domain		The domain distribution of the samples
W	The sample weight space		The sample weight of target domain sample
	The loss function		The weight mapping function
	The feature mapping function (feature extractor)		The classifier
	The feature representation distributions	,,	The parameter vectors of , and
n	The number of samples		The domain weight of the i-th source domain
m	The number of raw feature dimensions of the sample	s	The number of mapped feature dimensions of the sample