Hypothesis Class

Definition

Hypothesis Class

A hypothesis class is the set of all candidate functions (models) that a learning algorithm is permitted to select. It defines the search space of the learner. For supervised learning, the class is a subset of all possible mappings from instances to labels:

Inductive Bias and Capacity

The selection of represents the inductive bias of the learner, as it restricts the model to certain structural forms (e.g., linear functions, decision trees of depth ).

Expressiveness: The “richness” of the class is quantified by its VC dimension. A class with higher capacity can represent more complex patterns but requires a higher sample complexity to ensure generalisation and avoid overfitting.