-----maxima-bounces at math.utexas.edu wrote: ----- >For?second?order?ODEs,?contrib_ode?just?tries?ode2?then?odelin.??You >would?have? to?ask?Barton?Willis?why?he?wrote?it?that?way. Fewer cases, fewer checks. We like that. A user could user write a rule to convert bessel_j(n,%i * x) --> bessel_i(....). Barton