## subscript - creating multiple copies - business, housing, people (equation are not identical) - aging chain for ppl, housing, business are similar (exclude self-interaction) - Market[country, gender] = (3,4; 5,6) - if more than two dim -> read from database, cin file ### function - sum, vmin, vmax, vector selct aggregate; - TotalMarket[Country] = Sum(People[country, gender!, age!]) - matrix operations - product: vector product Z = sum(X[S!]* Y[S!]) Z[S, T] = sum(X[S!]*Y[S!]),