Algebra
Variables, equations, polynomials, abstract algebra
Subfields
Elementary Algebra
Variables, polynomials, factoring, equations, inequalities, systems
Advanced Algebra
Exponential, logarithmic functions, sequences, series, recurrence
Abstract Algebra
Group theory, ring theory, field theory, Galois theory
Boolean Algebra
Logical operations, logic gates, digital circuits
Representation Theory
Group representations, Lie algebras, physics applications
Homological Algebra
Chain complexes, homology, category theory applications
Concepts
Variables
★☆☆☆☆A symbol representing an unknown or changeable value.
Polynomial
★★☆☆☆An expression consisting of terms with variables and coefficients combined by addition.
Linear Equation
★☆☆☆☆An equation where the highest power of the variable is 1.
Factoring
★★☆☆☆Expressing a polynomial as a product of two or more polynomials.
Quadratic Equation
★★☆☆☆An equation where the highest power of the variable is 2.
Inequality
★★☆☆☆An expression showing the relationship between two values using inequality symbols.
System of Equations
★★☆☆☆A set of two or more equations that must be satisfied simultaneously.
Exponential Function
★★★☆☆A function where the base is a positive constant and the exponent is the variable.
Logarithm
★★★☆☆The inverse of exponential function, indicating how many times a base must be multiplied to get a number.
Arithmetic Sequence
★★☆☆☆A sequence where the difference between consecutive terms is constant.
Geometric Sequence
★★☆☆☆A sequence where the ratio between consecutive terms is constant.
Series
★★★☆☆The sum of terms in a sequence, which can be finite or infinite.
Tensor
★★★★☆A mathematical object defined as a multilinear map. A (p,q)-tensor has p covariant and q contravariant components.
Tensor Product
★★★★☆An operation constructing a new vector space from two vector spaces. Characterized by the universal property of bilinear maps.
Covariant/Contravariant
★★★★☆Transformation rules for components under coordinate changes. Covariant components transform like basis, contravariant oppositely.
Lie Group
★★★★★A group with smooth manifold structure. Group operations are differentiable, representing continuous symmetries.
Lie Algebra
★★★★★The tangent space at the identity of a Lie group, equipped with Lie bracket. Encodes infinitesimal structure of the group.
Exponential Map
★★★★★A map from Lie algebra to Lie group. Generates finite transformations from infinitesimal generators.
Classical Lie Groups
★★★★☆Fundamental Lie groups represented as matrices: GL(n), SL(n), O(n), SO(n), U(n), SU(n), Sp(n).
Adjoint Representation
★★★★★A representation of a Lie group acting on its own Lie algebra. Essential for studying Lie algebra structure.
Killing Form
★★★★★A symmetric bilinear form on a Lie algebra. Essential for determining semisimplicity and classification.
Root System
★★★★★A finite set of vectors encoding the structure of semisimple Lie algebras. Classified by Dynkin diagrams.
Semisimple Lie Algebra
★★★★★A Lie algebra with no solvable ideals. Decomposes as direct sum of simple Lie algebras; Killing form is non-degenerate.