It's mentioned on the Pukkelpop site as DDN indeed. Are you going?
Don't know what the Lowlands set is going to be yet as SY still has to be added to their site, but SY's myspace doesn't list it as Daydream Nation so it appears that it's not. But even if it will be then it's not that likely I'll be going either way. I haven't been to Lowlands in over 5 years and a return ticket to London is probably cheaper than the 120 euros or whatever a 3-day ticket for Lowlands costs nowadays.
Ironically, a friend of mine suggested a couple of months ago that we should go to Lowlands this year just for old times sake. I liked the idea of that, but I dont't really see it happening. First time I went there was when SY also played it in 1996. In an ideal world they'd do a Rather Ripped set at Lowlands and then add a DDN show at an indoor venue on the 20th or 21st before heading to Glasgow on the 22nd, but that's probably asking too much.
www.pukkelpop.be
www.lowlands.nl