Prior research on machine learning for text classification has primarily considered classification of documents by topic (Lewis, 1992;Yang, 1999), but also has addressed sentiment detection (Pang et al., 2002;Weibe et al., 2001) and authorship attribution (e.g., Argamon et al, 2003).
while a proposal is associated with a new task, an amendment is a suggested modification of an already-proposed task.