AN OBSTRUCTION TO SLICING ITERATED BING DOUBLES

Recent advances in understanding slicing properties of Bing doubles of knots have depended on properties of iterated covering links. We expand and refine this covering link calculus. Our main application here is a simplified proof of the following result of Cha and Kim: If the iterated Bing double of a knot K is slice, then K is algebraically slice. Further applications are included in joint work with Livingston studying 4-genera of Bing doubles. The techniques also appear in the work of Levine studying mixed Bing-Whitehead doubles.