Isogenies and Endomorphism Rings
Isogenies as maps of curves respecting the group law, and the two possible endomorphism rings over a field of characteristic zero.
Engineering articles and subject areas in the KEVOS knowledge library. 1397 pages.
Isogenies as maps of curves respecting the group law, and the two possible endomorphism rings over a field of characteristic zero.
Computing kernel and image bases for rectangular matrices over a field, and why the integer analogue is a different problem.
The kernel of a linear transformation: definition, why it is always a subspace, its role as the preimage of zero, and why a trivial kernel means injectivity.
The kernel and image of a homomorphism, and the first isomorphism theorem relating them to a quotient.
The L-function of an elliptic curve, the Birch-Swinnerton-Dyer conjecture, and what can and cannot be computed about rank.
Randomised complexity classes RP, co-RP, BPP and ZPP, and where primality testing sits among them.
Lattices as discrete subgroups, the Gram matrix, and the correspondence between lattices with a basis and positive definite quadratic forms.
The lattice determinant as a basis-independent invariant, the Hadamard inequality, and using the orthogonality defect to measure basis quality.
The identification of elliptic curves over the complex numbers with complex tori, and the Weierstrass function that realises it.
Suggested routes through the collection for cryptography, computer algebra, coding theory and pure mathematics readers.
Four routes through this 182-page collection, chosen by what you need to build rather than by chapter order.
The three quadratic symbols, their differing meanings, and the reciprocity-based algorithm that computes them without factoring.
Lehmer's method: running many GCD steps on single-precision leading digits before touching the full multiprecision operands.
A full blending and production-planning case study: mass balances as linear equations, unique versus infinite solution sets, feasibility bounds and profit optimisation.
A consolidated reference for linear algebra notation: matrices, entries, vectors, the four subspaces, spans, inner products, transformations and matrix representations.
How the theorems of linear algebra depend on one another: from row operations and RREF through span, bases and dimension to rank, determinants and eigenvalues.
How the theorems of linear algebra depend on one another: from row operations and RREF through span, bases and dimension to rank, determinants and eigenvalues.
Linear combinations of column vectors: definition, the equivalence between solving a linear system and writing a constant vector as a combination of columns.
Why a linearly dependent set always contains a vector expressible from the others, and how removing it shrinks a spanning set without changing the span it generates.
Linear independence, spanning sets and bases, and the conditions under which a basis exists.
Why a square matrix is nonsingular exactly when its columns are linearly independent, the chained proof, and the growing list of nonsingular equivalences.
Relations of linear dependence and linear independence in any vector space: the definitions, the reduction to a homogeneous system, and worked tests in matrix and polynomial spa…
Relations of linear dependence, the definition of a linearly independent set of column vectors, and the homogeneous-system and rank tests that decide it.
The definition of a linear transformation between vector spaces: additivity, homogeneity, the zero-to-zero theorem, and how to tell a linear map from an affine one.
A linear transformation passes through any linear combination, so its values on a basis determine it everywhere. The superposition theorem and its use in prediction.
Sequences satisfying linear recurrences, their minimal polynomials, and the equivalence with rational generating functions.
Extending LLL to generating sets that are not independent, and using the resulting zero vectors to extract relations.
Why LLL terminates in polynomial time and what its output guarantees, via the potential function and the Lovasz condition.
Allowing a vector to move further than one position, the quality gain, and the loss of the polynomial time guarantee.
Using lattice reduction to control entry growth during Hermite normal form computation, and when this beats the modular approach.
Lucas sequences, the Lucas probable prime test, and why it complements the strong pseudoprime test rather than duplicating it.
The random access machine and Turing machine models, what counts as a primitive operation, and how the choice of model affects stated complexities.
Markov's and Chebyshev's inequalities, their proofs, and how they bound deviation from the mean.
The notational conventions, symbol set and standing assumptions used throughout the KEVOS computational number theory collection.
What a matrix is, the entry notation for row and column, and how appending the constants column turns a system of linear equations into a single rectangular array.
The correspondence between matrices and linear maps, change of basis, and why the correspondence depends on a choice.
Every matrix defines a linear transformation, and every linear transformation on column vectors comes from one unique matrix built from images of the unit vectors.
Entrywise complex conjugation of a matrix, how it respects addition and scalar multiplication, commutation with the transpose, and the adjoint or conjugate transpose.
Matrices over a ring, their arithmetic, and the properties that survive when the base ring is not a field.
Column vectors, the zero vector, coefficient matrix, vector of constants and solution vector: the notation that compresses a whole system of equations into the symbol LS(A,b).
Entry-by-entry definitions of matrix equality, matrix addition and scalar multiplication on the set of m by n matrices, with worked examples and engineering use.
Matrix multiplication defined column by column through the matrix-vector product, the inner dimension rule, why the operation is not commutative, and what it means.
The entry formula for a matrix product: each entry of AB sums over the shared dimension, why it follows from the column definition, and what it costs.
Dense and sparse matrix representations, the cost model for exact linear algebra, and why coefficient growth rather than operation count usually decides performance.
Changing basis converts one matrix representation of a transformation into another by a similarity transformation, which is why eigenvalues and rank are intrinsic.
An invertible linear transformation has an invertible matrix representation, and the representation of its inverse is the matrix inverse with the bases exchanged.
How a linear transformation between abstract vector spaces becomes a matrix: the definition of a matrix representation, the fundamental theorem, and basis choice.
Definition of the matrix transpose, symmetric matrices, why symmetric matrices are square, and how the transpose interacts with matrix addition and scalar multiplication.