Questions about demand spread

The book often mentions the spread of demand, but there is never a general definition of the spread of demand.

Demand spread is an important aspect of product control.

I think to control the spread of demand, we must first understand what the spread of demand is, and secondly understand the reasons for the spread of demand.

 

However, the book does not provide the most basic information. On the Internet, you can only find people's questions about the spread of demand control.

The spread of demand is a general concept for me, but I cannot clearly understand it or clearly understand the cause.

 

Questions about demand spread