The Zoldan children died when the eldest was 6. But no memorial would list their names, no tombstones would mark their graves.That may be why Rose Rosen had never heard of them until last March when she interviewed a relative about family members who had died in the Holocaust.Rosen knew that her uncle’s wife had a sister who died at the Birkenau extermination camp with her husband. But she didn’t realize that Channah and Isaac Zoldan had children.They had three, said her aunt, a Sarasota resident who shares Rosen’s name. The baby, David, was just 18 months when they were killed. His sister, Gita, was 6, and his brother, Hirsh, was 4.