>proof that your program will terminate Or that a coprogram will be productive (services/servers/streaming fall under this). Most programs these days operate

>proof that your program will terminate Or that a coprogram will be productive (services/servers/streaming fall under this). Most programs these days operate on codata, so termination on a per-destructed-codata-component basis is productivity if I understand correctly. (ejenk touches on this in the comments as well, but I wanted to add this point)