Kronecker product

E102485

The Kronecker product is a matrix operation that forms a large block matrix from two smaller matrices and is widely used in linear algebra, quantum computing, and signal processing.

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Statements (50)

Predicate Object
instanceOf binary operation on matrices
matrix operation
alsoKnownAs direct product of matrices
tensor product of matrices
arity 2
definition Kronecker product self-linksurface differs
surface form: For an m×n matrix A and a p×q matrix B, A ⊗ B is the mp×nq block matrix whose (i,j)-th block is a_ij B
domain finite-dimensional vector spaces
eigenvalueRelation Eigenvalues of A ⊗ B are pairwise products of eigenvalues of A and B
field control theory
linear algebra
matrix theory
numerical analysis
quantum computing
signal processing
statistics
identityRelation I_m ⊗ I_n = I_{mn}
inputType matrix
matrix over a ring
inverseRelation If A and B are invertible then (A ⊗ B)^{-1} = A^{-1} ⊗ B^{-1}
linearity bilinear in both arguments
matrixSizeRule If A is m×n and B is p×q then A ⊗ B is mp×nq
namedAfter Leopold Kronecker
outputType matrix
property (A ⊗ B)(C ⊗ D) = AC ⊗ BD when dimensions are compatible
(A ⊗ B)^* = A^* ⊗ B^* for conjugate transpose
(A ⊗ B)^T = A^T ⊗ B^T
associative up to canonical isomorphism
compatible with scalar multiplication
det(A ⊗ B) = det(A)^p det(B)^m for A m×m and B p×p
distributive over matrix addition
non-commutative in general
rank(A ⊗ B) = rank(A) rank(B)
trace(A ⊗ B) = trace(A) trace(B)
relatedConcept Hadamard product
matrix direct sum
tensor product of vector spaces
vec operator
standardIdentity vec(AXB) = (B^T ⊗ A) vec(X) when dimensions are compatible
symbol \otimes
use construction of large structured matrices
discretization of partial differential equations
formulation of multi-qubit quantum gates
modeling composite quantum systems
multidimensional signal processing
representation of linear maps on tensor product spaces
separable covariance matrices in statistics
solution of large-scale linear systems
vectorization identities in matrix calculus
zeroRelation 0 ⊗ A = 0 and A ⊗ 0 = 0

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Full triples — surface form annotated when it differs from this entity's canonical label.

Leopold Kronecker notableWork Kronecker product
Kronecker product definition Kronecker product self-linksurface differs
this entity surface form: For an m×n matrix A and a p×q matrix B, A ⊗ B is the mp×nq block matrix whose (i,j)-th block is a_ij B