non-reducible

adjective

1. capable of being reduced.
2. Mathematics.
   1. of or relating to a polynomial that can be factored into the product of polynomials, each of lower degree.
   2. of or relating to a group that can be written as the direct product of two of its subgroups.
   3. of or relating to a set whose set of accumulation points is countable.

adj.mid-15c.; see reduce + -ible. Cf. Old French redusible.