Here is a link to the dissertation on Poulenc's Sonata for Horn, Trumpet and Trombone by John Cord (UNT), and here are a few excerpts from the paper:
On a larger scale it is interesting to note what might be considered an inconsistency in the delivery of important themes throughout the first and third movements. Poulenc chooses to use a variety of dynamics and articulations when the main themes re-enter. This is not an arbitrary adaptation of musical elements but a finely crafted musical pursuit. I believe that Poulenc is seeking to achieve a “textural shift” in the music at these various points. He uses an alternating pattern of articulations throughout the piece to develop an internal theme and variations structure. This alternating pattern of articulations is developed by applying a certain articulation to a part for a particular theme.
There is a mistake in the trumpet part pertaining to articulations found in m. 26. In this measure, the trumpet part is missing a slur over the group of four sixteenth notes. This is an obvious mistake the score containing all three parts does show the slur in the trumpet part, this particular figure is found two measures earlier in the part and does utilize the slur and the other two parts contain slurs in this measure. If this were a discrepancy in articulations in the first or third movement, the question may be raised as to whether this may be another example of Poulenc developing texture through articulations, but the second movement shows no inconsistencies in articulations whatsoever throughout the movement, making his intentions clear that they should remain consistent through the end of the movement.
Upon first glance it would seem that simple misprints and copying errors may be the cause of this inconsistent application of articulations. However, after closer examination, it is apparent that Poulenc‟s intention is to consistently create contradictions between the instruments. The combination of articulations between the three instruments for specific themes is never repeated in its exact state. This pursuit to create new textures through fluctuation of articulations is achieved in some cases through the alteration of even a single pitch, and in other cases, the lack of articulation marking is in fact the alterationRelated Links:
Official Poulenc Website
Pro Music Brass Trio Recording
Guy Touvron recording