exercise left as an

exec | = E = | Exon

exercise, left as an adj.

[from technical books] Used to complete a proof when one doesn't mind a handwave, or to avoid one entirely. The complete phrase is: "The proof [or `the rest'] is left as an exercise for the reader." This comment has occasionally been attached to unsolved research problems by authors possessed of either an evil sense of humor or a vast faith in the capabilities of their audiences.

exec | = E = | Exon