General Edge-isoperimetric Inequalities, Part I: Information-theoretical Methods

In combinatorics we often meet two kinds of extremal problems. In one kind, optimal configurations consist of ‘objects’, which are somehow uniformlyspreadin the space under consideration; and in the other kind, optimal configurations consist of ‘objects’, which are somehowcompressed.To the first kind belong packing, covering and coding problems, whereas diametric (especially of Erdös-Ko-Rado type), vertex- and edge-isoperimetric problems belong to the second kind.