This invention relates to novel 4–1,4-dihydropyridine of the following formula derivatives having protein tyrosine kinase inhibitory activity, to a process for the manufacture thereof and to the use thereof for the treatment of c-Met-mediated diseases or c-Met-mediated conditions, particularly cancer and other proliferative disorders. The method of producing the thin film magnetic head, in which a head substrate, magnetoresistance effect element, lower magnetic pole, write gap layer and an upper magnetic pole are formed in this order, has the lower magnetic pole patterned with a larger width than that of the upper magnetic pole in a write magnetic pole after the lower magnetic pole is formed. In this manner, an end user can accurately monitor the operating voltage at the voltage sensor point on the IC. The acceptable range of prices can be displayed on a graphical user interface using visual indicators.