Irrelevant features include the formal or dynamic characteristics of the stimulus and the formal or dynamic characteristics of the response.
A relationship between a discriminative stimulus and the response it controls with the following features:
The discriminative stimulus must have two or more components
The response must have two or more components
The first part of the stimulus must control the first part of the response, the second part of the stimulus must control the second part of the response, etc.
Formal or dynamic characteristics of the stimulus
Formal or dynamic characteristics of the response