Example of Masked Language Modeling with Single and Multiple Masks

In a masked modeling approach, an input sequence x is transformed into a modified sequence x̄ by replacing tokens at a randomly selected set of positions A(x) with a special [MASK] symbol. Given an input sequence x = (T1, T2, T3, T4, T5, T6) and a set of selected positions A(x) = {2, 5} (using 0-based indexing), what is the resulting modified sequence x̄?

Critique of a Masking Implementation

In the formal definition of the masking process used in language models, several components are used to describe the transformation of an input sequence. Match each symbolic component with its correct description.