《工业组织》（英文版）market concentration 1

Let q, denote the output (or sales) of firm i Then total output (or total sales) is given by where firms are ranked by size; 1.e. q, denotes the largest firm, etc. The share of total output (or total sales) of the ith firm is defined by: s: "41/Q and the mean output (or mean sales) by q-Q/N Title Definition (Equal shares )(One firm) s1 Herfindahl Index 2 ln(1/ Relative Entropy Hannah-Kay index=∑(s1 需E Relative Concentration Measures (Inequality Indice ete equality (qs-q)/N Gini coefficient G=(1/N)∑(N-2i+1s N-1)/N Logarithmic variance LV =N E(In(q, /g)) mean for firm size