  Typechecking consists of statically verifying whether the output of an XML
transformation always conforms to an output type for documents satisfying a
given input type. In this general setting, both the input and output schema as
well as the transformation are part of the input for the problem. However,
scenarios where the input or output schema can be considered to be fixed, are
quite common in practice. In the present work, we investigate the computational
complexity of the typechecking problem in the latter setting.
