subparameter

SubParameter is a term used in mathematics and computer science to describe a parameter that exists within the scope of a larger or primary parameter. A SubParameter is typically a subordinate component of a composite parameter, often representing a detail or constraint defined relative to the main parameter.

Formally, many models express parameters as a vector θ that can be partitioned into blocks: θ = (φ, ψ). Here ψ is a collection of SubParameter associated with φ. SubParameter may depend on φ, be conditioned on φ, or be defined by a hierarchical relationship. The concept is related to but not identical with nested parameters, hierarchical parameters, or dependent parameters.

In practice, SubParameter arises in hierarchical or modular models, in Bayesian inference when a prior or likelihood is parameterized by higher-level parameters, or in software design where a configuration parameter has SubParameter detailing specific options. Examples include a model with a main shape parameter and SubParameter specifying scale, orientation, or distributional assumptions; or a neural network where a layer's initialization depends on a shared hyperparameter.

Because SubParameter is not a standardized technical term across all fields, its precise meaning can vary. Definitions should specify scope, dependencies, and conditioning in context. Related concepts include nested parameters, conditional parameters, and hierarchical parameterization.