Let us use $S$ to denote the set of training categories and $T$ to denote the set of testing categories.
- $S=T$: the most common case
- $S\cap T=\emptyset$: zero-shot learning
- $S\subset T$: generalized zero-shot learning
- $S\supset T$: pretrained model
Let us use $S$ to denote the set of training categories and $T$ to denote the set of testing categories.