general system definitions

0.1 General dynamic systems descriptions as stable space-time structures

0.1.1 Introduction: General system description

A general system can be described as a dynamical ‘whole’, or entity capable of maintaining its working conditions; more precise system definitions are as follows.

Definition 0.1.

A simple system is in general a boundedPlanetmathPlanetmathPlanetmath, but not necessarily closed, entity– here represented as a categoryMathworldPlanetmath of stable, interacting components with inputs and outputs from the system’s environment, or as a supercategoryPlanetmathPlanetmath for a complex system consisting of subsystems, or components, with internal boundaries among such subsystems. In order to define a ‘system’ one therefore needs to specify the following data:

  1. 1.

    components or subsystems;

  2. 2.

    mutual interactions, relationsMathworldPlanetmathPlanetmathPlanetmath or links;

  3. 3.

    a separationPlanetmathPlanetmath of the selected system by some boundary which distinguishes the system from its environment, without necessarily ‘closing’ the system to material exchange with its environment;

  4. 4.

    the specification of the system’s environment;

  5. 5.

    the specification of the system’s categorical structureMathworldPlanetmath and dynamics (a supercategory will be required only when either the components or subsystems need be themselves considered as represented by a category , i.e. the system is in fact a super-system of (sub)systems, as it is the case of emergent super-complex systemsPlanetmathPlanetmath or organisms).

0.1.2 Remarks

Point (5) claims that a system should occupy either a macroscopic or a microscopic space-time region, but a system that comes into birth and dies off extremely rapidly may be considered either a short-lived process, or rather, a ‘resonance’ –an instability rather than a system, although it may have significant effects as in the case of ‘virtual particles’, ‘virtual photons’, etc., as in quantum electrodynamics and chromodynamics. Note also that there are many other, different mathematical definitions of systems, ranging from (systems of) coupled differential equations to operator formulations, semigroups, monoids, topological groupoidPlanetmathPlanetmathPlanetmathPlanetmath dynamic systems and dynamic categories. Clearly, the more useful system definitions include algebraic and/or topological structures rather than simple, discrete structure sets, classes or their categories. The main intuition behind this first understanding of system is well expressed by the following passage: “The most general and fundamental property of a system is the inter-dependence of parts/components/sub-systems or variables.”

Inter-dependence consists in the existence of determinate relationships among the parts or variables as contrasted with randomness or extreme variability. In other words, inter-dependence is the presence or existence of a certain organizational order in the relationship among the components or subsystems which make up the system. It can be shown that such organizational order must either result in a stable attractor or else it should occupy a stable space-time domain, which is generally expressed in closed systems by the concept of equilibrium.

On the other hand, in non-equilibrium, open systems, such as living systems, one cannot have a static but only a dynamic self-maintenance in a ‘state-space region’ of the open system – which cannot degenerate to either an equilibrium state or a single attractor space-time region. Thus, non-equilibrium, open systems that are capable of self-maintenance will also be genericPlanetmathPlanetmathPlanetmath, or structurally-stable: their arbitrary, small perturbation from a homeostatic maintenance regime does not result either in completely chaotic dynamics with a single attractor or the loss of their stability. It may however involve an ordered process of change - a process that follows a determinate, multi-stable pattern rather than random variation relative to the starting point.

0.2 General dynamic system definition

A formal (but natural) definition of a general dynamic system, either simple or complex can also be specified as follows.

Definition 0.2.

A general dynamic system SGD is a quintuple ([I,O],[λ:IO],S,[Δ:SS],𝔾B), where:

  1. 1.

    I and O are, respectively, the input and output manifolds of the system , SGD;

  2. 2.

    S is a category with structure determined by the components of SGD as objects and with the links or relations between such components as morphismsMathworldPlanetmath;

  3. 3.

    Δ:SS is the ‘dynamic transition’ functorMathworldPlanetmath in the functor categoryPlanetmathPlanetmath AutS of system endomorphismsPlanetmathPlanetmath (which is endowed with a groupoidPlanetmathPlanetmathPlanetmath structure only in the case of reversible, closed systems);

  4. 4.

    λ is the output ‘function or map’ represented as a manifold homeomorphism;

  5. 5.

    𝔾B is a topological groupoid specifying the boundary, or boundaries, of SGD.

Remark. We can proceed to define automata and certain simpler quantum systems as particular, or specialized, cases of the above general dynamic system quintuple.

Title general system definitions
Canonical name GeneralSystemDefinitions
Date of creation 2013-03-22 18:19:02
Last modified on 2013-03-22 18:19:02
Owner bci1 (20947)
Last modified by bci1 (20947)
Numerical id 31
Author bci1 (20947)
Entry type Topic
Classification msc 93A30
Classification msc 93A05
Classification msc 93A13
Classification msc 93A10
Synonym dynamic system
Synonym dynamic structure
Synonym general system
Related topic SimilarityAndAnalogousSystemsDynamicAdjointness2
Related topic CommutativeVsNonCommutativeDynamicModelingDiagrams
Related topic GroupoidCDynamicalSystem
Related topic AutonomousSystem
Related topic SystemState
Related topic RelationalSystem
Related topic LinearTimeInvariantLTISystems
Related topic DynamicalSystem
Related topic Observability
Related topic ControlSystems
Defines general dynamic system
Defines complex system
Defines system dynamics
Defines configuration space algebraic topology
Defines qualitative dynamics
Defines dynamic configuration functors
Defines qualitative biodynamics
Defines super-complex system
Defines generating class
Defines dynamic multi-stability
Defines biodynamics
Defines q