TheoremBase

Maps Formed Pointwise from Vector and Matrix Operations

Sums, scalar multiples, negatives, differences, products, matrix-vector products, transposes and inverses of matrix- and vector-valued maps on a set, taken pointwise, are well-defined maps.

Statement

In the setting of Euclidean Space and Real Matrices: Standing Notation, let SS be a set and let p,q,r∈Np,q,r\in\mathbb{N}. Sums, scalar multiples, negatives and differences of points of Rq\mathbb{R}^{q} and of matrices are those of Euclidean Space and Real Matrices: Standing Notation (ii) and Euclidean Space and Real Matrices: Standing Notation (iii); the matrix product, the matrix-vector product and the transpose are those of Euclidean Space and Real Matrices: Standing Notation (iii); and invertible matrices and their inverses are as in Euclidean Space and Real Matrices: Standing Notation (x). Let f,g:S→Mp×q(R)f,g:S\to\mathcal{M}_{p\times q}(\mathbb{R}), h:S→Mq×r(R)h:S\to\mathcal{M}_{q\times r}(\mathbb{R}), x,y:S→Rqx,y:S\to\mathbb{R}^{q} and φ:S→R\varphi:S\to\mathbb{R} be maps.

There is exactly one map S→Mp×q(R)S\to\mathcal{M}_{p\times q}(\mathbb{R}) whose value at every u∈Su\in S is f(u)+g(u)f(u)+g(u), and likewise exactly one such map with values φ(u)f(u)\varphi(u)f(u), exactly one with values −f(u)-f(u) and exactly one with values f(u)−g(u)f(u)-g(u). There is exactly one map S→Mp×r(R)S\to\mathcal{M}_{p\times r}(\mathbb{R}) with values f(u)h(u)f(u)h(u), exactly one map S→RpS\to\mathbb{R}^{p} with values f(u)x(u)f(u)x(u), and exactly one map S→Mq×p(R)S\to\mathcal{M}_{q\times p}(\mathbb{R}) with values f(u)⊤f(u)^{\top}. There is exactly one map S→RqS\to\mathbb{R}^{q} with values x(u)+y(u)x(u)+y(u), and likewise exactly one with values φ(u)x(u)\varphi(u)x(u), exactly one with values −x(u)-x(u) and exactly one with values x(u)−y(u)x(u)-y(u). These maps are written u↦f(u)+g(u)u\mapsto f(u)+g(u), u↦φ(u)f(u)u\mapsto\varphi(u)f(u), and so on.

If p=qp=q and f(u)f(u) is invertible for every u∈Su\in S, then there is exactly one map S→Mp(R)S\to\mathcal{M}_{p}(\mathbb{R}) whose value at every u∈Su\in S is f(u)−1f(u)^{-1}; it is written u↦f(u)−1u\mapsto f(u)^{-1}.

Proofs

Log in to submit a proof.

Loading...

Citations

Loading…

Dependencies

Loading…

Related

0 relations

Curated associations between results. These are editable and subjective — they do not replace the dependency graph, which is derived from the references in the text.

No relations recorded yet.

Comments

Log in to comment.

Loading…