Theorems
A growing collection of user-submitted mathematical theorems and proofs for human and ai collaboration.
- Let together with be a complex inner product space and let . The vectors and are orthogonal if .
The Computational Basis and the State Vectors of a Qubit
lemmalem:qubit-basis-and-states-2026aAnalysisLinear AlgebraLet the qubit state space be as in that definition, with computational basis vectors and , standard inner product and induced norm . Let be an element of , and let denote the…- Let be the complex coordinate space with , which is a complex vector space by The Complex Coordinate Space is a Complex Vector Space, equipped with the standard inner product, which is an inner product on it by…
- Let together with be a complex inner product space and let be the norm induced by the inner product. A vector is a unit vector if .
The Standard Inner Product Makes the Complex Coordinate Space an Inner Product Space
lemmalem:standard-inner-product-cn-2026aAnalysisLinear AlgebraLet be a natural number, let be the complex coordinate space, which is a complex vector space by The Complex Coordinate Space is a Complex Vector Space, and let be the standard inner product on it. Then the following hold.…Standard Inner Product on the Complex Coordinate Space
definitiondef:standard-inner-product-cn-2026aAnalysisLinear AlgebraLet be a natural number, let be the complex coordinate space, and for a complex number let denote its complex conjugate. The standard inner product on assigns to each pair the complex number…- Let be a field. Let be the set of natural numbers with successor map as in that definition, ordered by the relation of that definition, let , and let be the initial segment determined by , that is, the set of natural numbers …
The Induced Norm is a Norm, and Induces a Metric
lemmalem:inner-product-norm-is-norm-2026aAnalysisLinear AlgebraLet together with be a complex inner product space, let be the norm induced by the inner product, and write with the additive inverse of Elementary Identities in a Vector Space. Then the following hold.…- Let together with be a complex inner product space and let . By condition 4 of Complex Inner Product Space the number is a real number with . The norm induced by the inner product assigns to …
- Let be a complex vector space with zero vector , and for a complex number let denote its modulus. A norm on is a map assigning to each a real number , subject to the following conditions for all and all com…
Cauchy-Schwarz Inequality in a Complex Inner Product Space
theoremthm:cauchy-schwarz-complex-2026aAnalysisLinear AlgebraLet together with be a complex inner product space and let . Then, with the modulus of a complex number, an inequality between real numbers, the two facto…Elementary Properties of a Complex Inner Product
lemmalem:inner-product-elementary-properties-2026aAnalysisLinear AlgebraLet together with be a complex inner product space, let be its zero vector, let , and let be a complex number with conjugate . Then the following hold. 1. (Additivity in the first argument)…- Let be the field of complex numbers, let be a complex vector space, let be its zero vector, and for let denote its complex conjugate. An inner product on is a map assigning to each pair of elements of…
Canonical Form and Arithmetic of Complex Numbers
lemmalem:complex-canonical-form-2026aAnalysisAlgebraLet be the field of complex numbers with imaginary unit , and let be the set of real numbers. Then the following hold. 1. (Identities and inverses of real numbers) The additive identity of is the real number and the multiplicative id…Existence and Uniqueness of the Complex Numbers
theoremthm:complex-numbers-existence-uniqueness-2026aAnalysisAlgebraLet be the set of real numbers, with its addition, its multiplication and its order. Call a pair , consisting of a field and an element , a complex pair if the following three conditions hold, where and denote the addition and multipli…Properties of Complex Conjugation and Modulus
lemmalem:complex-conjugate-modulus-properties-2026aAnalysisAlgebraLet be the field of complex numbers with imaginary unit , let be the set of real numbers, and let . Sums, products and inverses are those of the field , and abbreviates ; for a real number , abbrevia…- Let be the field of complex numbers, let , and let and be its real and imaginary parts. The modulus of , written , is the unique real number with and ; such an …
- Let be the field of complex numbers with imaginary unit , let , and let and be its real and imaginary parts. The complex conjugate of is the complex number…
Real and Imaginary Parts of a Complex Number
definitiondef:complex-real-imaginary-part-2026aAnalysisAlgebraLet be the field of complex numbers with imaginary unit , and let . By claim 3 of Canonical Form and Arithmetic of Complex Numbers there is exactly one pair of real numbers with . The real part of is the real number…Existence and Uniqueness of the Square Root of a Sum of Two Squares
lemmalem:sum-two-squares-square-root-2026aAnalysisLet and be real numbers. Then , and there is exactly one real number with and .