Question $12$

What does the following notation mean: $[A2\}q,$

A$2$ is a key attribute for the candidate key A$1$

All tuples in R$2$ are a subset of R$1$

A$.2$ is a partial key for the weak entity $R2$ and is identified by $A1$

All values of R$2.$A$2$ must be in the set of values found in R$1.$A$1$