The concept establishes the abstract theory of mutable sequence containers within dynamic programming languages, defining the data structure as a heterogeneous array where elements are stored in contiguous memory blocks. It formalizes the mechanism of in-place modification, governed by a specific rule allowing the structural or content state of the object to change without generating a new memory allocation for the container itself. This theory operates within the domain of computer science, specifically the subfield of data structure theory, distinguishing between value semantics and reference semantics regarding sequence objects.
Prerequisite chain context: requires Variable Assignment as Reference Binding in Python.