Premise: The 1997 Porsche Tennis Grand Prix was a women's tennis tournament played on indoor hard courts at the Filderstadt Tennis Club in Filderstadt in Germany that was part of Tier II of the 1997 WTA Tour. It was the 20th edition of the tournament and was held from 6 October through 12 October 1997. First-seeded Martina Hingis won the singles title, her second consecutive at the event.
Hypothesis: The 1997 Porsche Tennis Grand Prix took place in 1999