[Avoid using mathematical terms and symbols when you explain, try to using simple English]
In the 12-products.pdf file,
1. Can you explain/rephrase what is "indexed set of sets" in another word?
2. Please give another easy to understand example?
In the 12-releation.pdf file,
1. Why a relation schema is an indexed set of sets?
2. Why a relation is a subset of a product?
3. Why the states of a relation schema are the subsets of schemas product? Please give an example?