ABSTRACT
In this paper we discuss general properties of non-linear dynamics. Our goal is to initiate a systematic exploration of this important field and therefore we try to raise new questions as much as we try to answer those which were already stated. We consider two basic types of evolution equations: the non-linear wave equation (NLWE) () − ∂ 2 u ∂ t 2 = H u + f ϵ ( u ) , https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003072096/6e6221c8-364d-4a5e-bfe5-98bb034e69b7/content/eq3093.tif"/>
