How does a slow introduction affect a sonata-form movement?

In the context of sonata form, a slow introduction is an optional section that may precede the main movement.1

It is important to note that while an introduction can set a specific mood or provide a dramatic opening, it does not affect the fundamental structure of the sonata-form movement itself. The core architecture of the movement remains defined by its three-part structure: the exposition, development, and recapitulation. Like the coda, the introduction is considered an auxiliary component rather than an essential element of the form's internal logic.12