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Chapter 7. Dual Numbers and Algebraic Structures

Dual numbers give the cleanest algebraic model of forward mode automatic differentiation. They extend ordinary real numbers with a formal infinitesimal part. Instead of...

SectionTitle
1Chapter 7. Dual Numbers and Algebraic Structures
2Nilpotent Elements
3Geometric Interpretation
4Truncated Polynomial Algebras
5Hyper-Dual Numbers
6Differential Algebras
7Category-Theoretic View
8Differential Lambda Calculus
9Differential Lambda Calculus
Chapter 7. Dual Numbers and Algebraic StructuresDual numbers give the cleanest algebraic model of forward mode automatic differentiation. They extend ordinary real numbers with a formal infinitesimal part. Instead of...
6 min
Nilpotent ElementsThe defining feature of dual numbers is the existence of a nonzero element whose square vanishes:
6 min
Geometric InterpretationDual numbers provide an algebraic mechanism for differentiation, but they also have a precise geometric meaning. A dual number represents a point together with an...
6 min
Truncated Polynomial AlgebrasDual numbers capture first-order derivatives because the infinitesimal element satisfies
5 min
Hyper-Dual NumbersDual numbers compute first derivatives exactly. Truncated polynomial algebras extend this to higher-order derivatives, but practical higher-order differentiation introduces an...
5 min
Differential AlgebrasDual numbers and hyper-dual numbers are special cases of a broader algebraic structure called a differential algebra. This framework abstracts differentiation away from...
6 min
Category-Theoretic ViewAutomatic differentiation can be described operationally through dual numbers and computational graphs. It can also be described abstractly using category theory.
6 min
Differential Lambda CalculusAutomatic differentiation is deeply connected to functional programming and lambda calculus. Programs can be viewed as mathematical functions, and differentiation can be...
6 min
Differential Lambda CalculusAutomatic differentiation is deeply connected to functional programming and lambda calculus. Programs can be viewed as mathematical functions, and differentiation can be...
6 min