Hello , I don't understand this formula.
At link :https://www.energycommunity.org/Help/index.htm#t=Demand%2FStock_Analysis_Calculations.htm
mso-fareast-theme-font:minor-latin;mso-ansi-language:EN-US;mso-fareast-language:
EN-US;mso-bidi-language:AR-SA">of this symbol ∑ What is the sub index and top index? y-v and 0 ??