What is an example of ambiguity in a piece of literature?
Many novels have ambiguous endings, like The French Lieutenant's Woman and Song of Solomon.
John Fowles' The French Lieutenant's Woman has three different endings, which is certainly ambiguous in a deliberate kind of way. (Charles marries Ernestina, Charles leaves the door open to reuniting with Sarah, Charles runs away from both of them forever, if I recall correctly.) The film of the book wittily tackles two of these endings by having one be about the characters and another about the actors portraying them.
Another novel with an ambiguous ending is Toni Morrison's Song of Solomon. The major plot conflict is between Milkman (the protagonist) and Guitar, his best friend growing up and his mortal enemy after a dispute over a large cache of gold. (Think of Tom Sawyer and Huckleberry Finn, only they're African-American, Tom's a gangsta and Huck's a fringe radical with a growing and indiscriminant body count.) The novel ends with Guitar taking a flying leap towards the waiting Milkman, but it cuts off in mid-leap. Who wins? Who lives? Does it ultimately matter?