  In this article, a generalized Kleinian sigma function for an affine (3,4,5)
space curve of genus 2 was constructed as the simplest example of the sigma
function for an affine space curve, and in terms of the sigma function, the
Jacobi inversion formulae for the curve are obtained. An interesting relation
between a space curve with a semigroup generated by (6,13,14,15,16) and Norton
number associated with Monster group is also mentioned with an Appendix by
Komeda.
