The document discusses European Union competition law regarding mergers. It defines different types of mergers like horizontal, vertical, and conglomerate mergers. It explains the purpose of merger control is to maintain competition and prevent the formation of monopolies that could harm consumer welfare. Merger control evaluates whether a merger could allow the merging companies to unilaterally exercise power over the market and reduce competition. Theories of potential competitive harm from mergers include unilateral or non-coordinated effects where competition between the merging companies' products is eliminated.