The finale of Dvorak 9 in E minor cadences D7/A - E. I heard from somewhere that it can be viewed as one kind of a plagal cadence and I'm wondering if that's true.
Strictly speaking, there is only one type of plagal cadence: IV (or iv) moving to I (or i).
However, the cadence in question does have important features in common with a plagal cadence.
- Like a plagal cadence, it contains a strong movement from ^4 to ^1. All of the lowest instruments in each section play A moving to E. The presence of C in the chord also helps suggest A minor.
- Also like a plagal cadence, it lacks a leading tone. To quote William Caplin (by way of Wikipedia)
the progression IV–I cannot confirm a tonality (it lacks any leading-tone resolution)
However, at this point in the piece, E minor has been firmly establish, and since the tonic E is well in one's ears, the transition to E major doesn't require a strong leading-tone motion, just a transitional harmony, which the D7 provides.