Within each cluster a number of well defined new Control Theory problems are introduced, which may be studied within the structural methodologies framework of Linear Systems.
Although the idea is relatively well defined in control theory, it brings difficulties and challenges to determine the stability of the impulsive differential equation due to a combination of current and past error states.
Perturbation theory gives well defined predictions only in renormalizable quantum field theories, and luckily QED, the first fully developed QFT, belonged to this class of renormalizable theories.
However, while it is an extremely powerful exploratory data analysis tool, and is well defined from the information theory perspective, PCA-derived components lack physical constraints.
Thirdly, the abundance of theories and their poor evidence base highlights the need to develop and trial interventions that utilise these theories appropriately (i.e. in concordance with the theory), with well defined and operationalised variables.
The phenomenon is well defined in terms of the theory of stability with a classic perturbation approach being commonly used.
TRIZ theory offers well defined and structured methods and tools, and allows generation of generic guidelines for innovative design of a huge variety of products.
From a modern perspective, we say that QED is not well defined as a quantum field theory to arbitrarily high energy.
The contact guidance theory was well defined by Curtis et al [ 33] as reaction of the growing cell to discontinuities of the underlying substratum.
It follows that the index numbers of ((0,0) ) and ((0, theta)) are well defined by using the fixed point theory as the following lemmas.
