# Utility classes
Underlying the implementations of [mlpack's machine learning
algorithms](../index.md) are mlpack core support classes, each of which are
documented in the pages below:
* [Core math utilities](core/math.md): utility classes for mathematical
purposes
* [Distances](core/distances.md): distance metrics for geometric algorithms
* [Distributions](core/distributions.md): probability distributions
* [Kernels](core/kernels.md): Mercer kernels for kernel-based algorithms
* [Trees](core/trees.md): space partitioning trees and other geometric tree
structures
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