Martín Fiz Martín Fiz Martín Fiz Martín (born 3 March 1963 in Vitoria-Gasteiz, Álava) is a former long-distance runner from Spain, who won the marathon at the 1994 European Championships in Athletics in Helsinki and repeated his success at the 1995 World Championships in Athletics in Gothenburg. The same year he captured the title in the Rotterdam Marathon. At the 1996 Summer Olympics in Atlanta Fiz came fourth in the Athletics at the 1996 Summer Olympics - Men's marathon. A year later he won a silver medal at the 1997 World Championships in Athletics in Athens, finishing behind his countryman Abel Anton.
Abel equation Abel equation The Abel equation, named after Niels Henrik Abel, is a type of functional equation which can be written in the form or, equivalently, and controls the iteration of . These equations are equivalent. Assuming that is an invertible function, the second equation can be written as Taking , the equation can be written as For a function assumed to be known, the task is to solve the functional equation for the function , possibly satisfying additional requirements, such as . The change of variables , for a real parameter , brings Abel's equation into the celebrated Schröder's equation,