Abstract: Among other things, improvements are made in the operation of a computer that processes input data values and generates internal data values that depend on the input data values and on mappings defining the processing. Input data values are received from input data sources. The input data values conform to input data concepts. The input data values are processed to map them according to specified mappings to internal data values that conform to internal data concepts. At least one of the mappings is (a) from input data values that conform respectively to two or more different input data concepts or (b) to internal data values that conform respectively to two or more different internal data concepts, or (c) both. Updated information is applied about characteristics of at least one of the mappings that will affect the internal data values that are the result of the processing, the information being updated as late as the beginning of the processing of the input data values.