Essential complexity
Essential complexity is the unavoidable difficulty inherent in a problem’s domain, rules, and required outcomes, which cannot be removed without sacrificing necessary behavior.
Collaborative Software Design: How to facilitate domain modeling decisions
Essential complexity is the irreducible complexity inherent in the problem domain that software design can manage but not eliminate.
- How it is used
- Guides bounded-context decisions by balancing local simplicity against communication complexity across boundaries.
- How deep it goes
- Explains the design trade-off and recommends modeling communication, but stops short of prescribing a complexity metric.
- Examples
- Uses alternative bounded-context designs and a group's concern about communication between split contexts.
- What you can do after
- Apply it via domain message flow modeling to compare boundary designs before implementation.
Functional Design and Architecture: Examples in Haskell
Complexity inherent in the problem domain that cannot be removed without failing to support required behavior.
- How it is used
- Frames software design around distinguishing unavoidable domain demands from complexity introduced by implementation choices.
- How deep it goes
- Defines unavoidable complexity and illustrates it through architecture, then stops before measuring or formally decomposing complexity.
- Examples
- Uses spaceship redundancy, recovery codes, subsystem commands, and differing booster and rotary-engine APIs.
- What you can do after
- Evaluate/understand which complexity required behavior imposes and which abstraction choices can keep implementation concerns manageable.
Read how Functional Design and Architecture: Examples in Haskell explains essential complexity →
Related concepts
- complexitykind of · Complexity is the degree of difficulty in understanding, analyzing, changing, or operating a system or problem, arising from its structure, behavior, or interacting parts.
- accidental complexitycontrasts with · Accidental complexity is difficulty arising from implementation choices or technical constraints rather than from the essential requirements of the problem being solved.
- bounded contextcontrasts with · A bounded context is a defined boundary within which a domain model, terminology, and associated rules have consistent meaning and application.
- intrinsic loadequivalent to · Intrinsic load is the mental effort required by the inherent complexity, difficulty, and interactivity of a task or subject matter.
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