irreducible

Not able to be reduced or lessened.

With each reduction in the number of railways, there must come, eventually, a decline in interest, if only through reduction in variety; and when it comes to one nationalised railway only we have reached the irreducible minimum.

Not able to be brought to a simpler or reduced form.

Unable to be factorized into polynomials of lower degree, as (x² + 1).

Whose numerator and denominator share no common factor greater than 1.

Unable to be factored into smaller integers; prime.

Such a polynomial