This book collects many of H.D. Bui's works mostly in French, and mostly unknown to the English scientific community, in the fields of Duality, Symmetry in Conservation Laws, Complementarity and Symmetry Lost. These concepts are seldom fully recognized in the literature and, in this sense, this book is unique.

To quote Bui : "Duality is synonym of parallelism, or complementary things, sometimes opposite things, tied together in an integral whole". The concept of Duality is closely linked to the concept of "virtual power" in the Mechanics of continuous media ; it originates from the concept of spaces and dual spaces of functions in mathematics culminating in the Theory of Distributions by Laurent Schwarz. H.D. Bui exploited the richness of duality to solve elegantly some important and deep inverse engineering problems presented in this book.

• Duality, symmetry and conservation laws
• Duality, symmetry and inverse problems
• Application to fracture mechanics, plasticity and damage