Mathematical Foundations for Machine Learning #
Machine Learning is built on mathematical principles that allow models to:
- represent data
- learn patterns
- optimise performance
flowchart LR
DATA[Data]
MATH[Math Models]
OPT[Optimisation]
MODEL[Trained Model]
DATA --> MATH
MATH --> OPT
OPT --> MODEL
ML requires core mathematical tools to understand how ML algorithms work internally. Algebra deals with relationships between variables and quantities, while Calculus focuses on change and optimization.
Core Mathematical Pillars in Machine Learning #
flowchart TB
ML[Maths for Machine Learning]
LA[Linear Algebra]
PR[Probability]
ST[Statistics]
CA[Calculus]
GR[Graphs]
ML --> LA
ML --> PR
ML --> ST
ML --> CA
ML --> GR
%% Colours (your pastel scheme)
style ML fill:#E1F5FE,stroke:#333
style LA fill:#C8E6C9,stroke:#333
style PR fill:#BBDEFB,stroke:#333
style ST fill:#90CAF9,stroke:#333
style CA fill:#64B5F6,stroke:#333
style GR fill:#FFCCBC,stroke:#333
- Linear Algebra
- Calculus
Why Mathematics Matters in ML #
- Machine learning models are mathematical functions
- Training a model means optimising equations
- Understanding maths helps to:
- Debug models
- Improve performance
- Choose the right algorithms
mindmap
Mathematics for Machine Learning
Linear Algebra
Vectors
Matrices
Eigenvalues
Matrix Multiplication
Probability
Random Variables
Probability Distributions
Conditional Probability
Bayes Theorem
Statistics
Mean
Variance
Sampling
Hypothesis Testing
Calculus
Derivatives
Gradients
Chain Rule
Optimisation
Graphs
Line Plots
Loss Curves
Decision Boundaries
Data Visualisation
Key Mathematical Areas
1. Linear Algebra #
Used to represent and manipulate data.
- Scalars, vectors, and matrices
- Matrix multiplication
- Eigenvalues and eigenvectors
- Vector spaces and projections
Used in:
- Neural networks
- Embeddings
- Principal Component Analysis (PCA)
2. Probability Theory #
Used to model uncertainty.
- Random variables
- Probability distributions
- Expectation and variance
- Conditional probability
Used in:
- Classification
- Bayesian models
- Uncertainty estimation
3. Statistics #
Statistics enables estimation, inference, and model evaluation from data samples.
Key Topics
- Mean, variance, and standard deviation
- Sampling and estimation
- Hypothesis testing
- Bias–variance trade-off
Used in:
- Model evaluation
- Error analysis
- Experimental validation
4. Calculus #
Used to optimise models during training.
- Derivatives and gradients
- Partial derivatives
- Chain rule
- Gradient descent
Used in:
- Backpropagation
- Loss minimisation
- Model training
5. Graphs #
Graphs are used to visualise data and learning behaviour.
Key Topics
- Line plots and scatter plots
- Loss curves
- Decision boundaries
- Convergence plots
Used in:
Analysing training behaviour
Debugging models
Explaining results
Optimisation (Cross-Cutting Concept) #
Optimisation is the process of finding the best model parameters by minimising or maximising an objective function.
- a mechanism that relies on multiple mathematical areas.
Depends on:
- Linear Algebra → parameter updates
- Calculus → gradient computation
- Probability & Statistics → loss functions
- Graphs → convergence analysis
Used in:
- Gradient descent and its variants
- Training deep neural networks
- Regularisation and generalisation
Concept checklist #
Linear systems and matrices #
- Convert equations into matrix form
Ax = b - Understand solution types: no solution, unique solution, infinite solutions
- Identify pivot and free variables
- Understand row operations, REF/RREF, rank, nullity
- Know matrix inverse and transpose properties
Vector spaces #
- Definition of vector space and subspace
- Closure under addition and scalar multiplication
- Span, linear combination, linear independence
- Basis, dimension, rank
- Column space, row space, nullspace
Analytic geometry #
- Norm properties
- Manhattan norm and Euclidean norm
- Inner product definition
- Symmetric positive-definite matrices
- Distance, angle, orthogonality
- Orthonormal basis and Gram-Schmidt
Matrix decompositions #
- Determinant and trace
- Cofactor expansion
- Row operation effect on determinant
- Eigenvalue equation
Av = λv - Characteristic equation
det(A - λI) = 0 - Diagonalisation
A = PDP^{-1} - Spectral theorem for symmetric matrices
- Cholesky decomposition
- SVD
A = UΣV^T - Low-rank approximation
Vector calculus #
- Derivative from first principles
- Partial derivatives
- Gradient as direction of steepest ascent
- Gradient of vector-valued functions
- Matrix-gradient identities
- Chain rule
- Backpropagation and automatic differentiation
Taylor series and Hessian #
- Taylor polynomial
- Taylor series and Maclaurin series
- Remainder term
- Taylor series in two variables
- Hessian matrix
- First derivative and second derivative tests
- Maxima, minima and saddle points
Gradient descent and optimisation #
- Negative gradient direction
- Learning rate/step size
- Line search
- Convergence and local minima
- Constrained vs unconstrained optimisation
- Lagrange multipliers
- Convex optimisation
- SGD and optimisation in ML
- Feature preprocessing and scaling
- Overfitting in optimisation examples
Nonlinear optimisation algorithms #
- Difficult surfaces: cliffs, valleys, flat regions
- Curvature and why first-order methods can struggle
- Momentum update and intuition
- AdaGrad
- RMSProp
- Adam
- Learning rate decay
PCA #
- Dimensionality reduction problem
- Centred data and covariance matrix
- Maximum variance view
- Projection/reconstruction view
- Principal components as eigenvectors of covariance matrix
- SVD relation to PCA
- Low-rank approximation and Eckart-Young theorem
- PCA in high dimensions
- Practical PCA steps
SVM #
- Linear classifiers
- Margin and support vectors
- Hard-margin SVM primal formulation
- Lagrangian for SVM
- KKT conditions
- Primal vs dual perspective
- Role of inner products
- Kernel trick
- Hinge loss
- Soft-margin SVM