THEORY. quantity competition. mergers between cournot competitors. mergers under non-cournot. PRICE COMPETITION. mergers betwen sellers of differentiated products. sumamary. OTHER STRATEGIC VARIABLES. multi-brant firms. quantity competition. price competition. POLICY. policy implications. the antitrust authorities. objetive. external welfare. consumer surplus. MERGERS SIMULATION. homogeneous production and quantity competition. constant marginal costs. increasing marginal consts. MERGERS CASES. the 2003 CIN/ibercoat concentration. the relevant market. the concentration level before and after the operation.