Abstract: | In the presence of closely located inclusions of the extreme material prop-erty,the physical fields,such as the electric field and the stress tensor,may be con-centrated and arbitrarily large in the narrow region between two inclusions.Recently there has been significant progress on the quantitative characterization of the field con-centration in the contexts of electrostatics(Laplace equation),linear elasticity(Lame system),and viscous flow(Stokes system).This paper is to review such progress in a coherent way. |