The king is dead

King Basil has died without saying who should rule next.

To find the rightful heir, we look at the royal family records, given as parent and deceased facts:

parent("basil", "edmund").  parent("basil", "diana").    parent("basil", "george").
parent("edmund", "alice").  parent("edmund", "bob").     parent("diana", "eve").
parent("diana", "frank").   parent("george", "henry").   parent("george", "kate").
parent("bob", "carol").

deceased("basil"). deceased("edmund"). deceased("bob"). deceased("george").