The archetype for the questions considered is: “Which plane oriented curves in the plane are representable as the images of the boundary of a disk under holomorphic function?” This question is equivalent to: “Which immersion of the circle in the plane are extendable to smooth sense preserving (= non-negative jacobian) mappings of the closed disk with the jacobian positive on the boundary?”The second question is generalized in terms of the genus and dimension of the source and target. An exposition...