A Hilbert space $H$ is a real or complex vector space endowed with an inner product such that $H$ is a complete metric space when endowed with the norm induced by this inner product.

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**1**answer

### Unbounded version of continuous functional calculus

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**1**answer

### Optimal estimate in trace norm

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### In which Hilbert space H^k is the Heaviside (Step) function? [closed]

**3**

**0**answers

### Hilbert space separability for spectral triples

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### Why is $H^{1/2}$ a Hilbert space?

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**0**answers

### Is the Green operator a trace class operator?

**2**

**1**answer

### Fredholmness of formal selfadjoint operator $AA^*$ and Fredholmenss of $A$

**3**

**0**answers

### A question about a theorem in 'Quantum dynamical semigroups generated by noncommutative unbounded elliptic operators'

**3**

**1**answer

### Measurability of specific function

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**1**answer

### Orthogonal complement vector space

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**0**answers

### Injective differential of linear operators on a Hilbertspace

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### A Question on certain Hilbert space of continuous functions, and a characteristic of convergence in it

**3**

**0**answers

### Constant in trace theorem for balls

**1**

**1**answer

### The tensor product of two bounded operators

**3**

**1**answer

### What is the consistency strength of non-existence of outer automorphisms of Calkin algebra?

**5**

**1**answer

### Fell's trick for Lie groups

**1**

**1**answer

### Completeness of Lowner order in separable Hilbert space

**3**

**1**answer

### Completely Positive Maps and their dual in Separable Hilbert Space

**10**

**2**answers

### $x f'$ bounded by $x^2f $ and $f''$?

**1**

**0**answers

### “Barrier functions” in function spaces [closed]

**2**

**1**answer

### Insights about a frame-like inequality

**4**

**1**answer

### Extending maps from dense $*$-algebras of $C^*$-algebras

**0**

**0**answers

### Uniform convergence in Hadamard derivatives

**3**

**1**answer

### Convergence of nuclear operators

**0**

**1**answer

### Convergence rate of eigenvectors

**7**

**1**answer

### Subspaces isomorphic with quotients

**1**

**0**answers

### A nested sequence of closed subspaces of $\ell^2$

**1**

**1**answer

### On projection theory for inseparable Hilbert spaces

**3**

**0**answers

### Araki's proof of simple connectedness of the restricted orthogonal group

**2**

**2**answers

### Point spectrum of a positive invertible operator

**4**

**1**answer

### The largest topological copy of a Hilbert space contained in $\ell^1$

**2**

**0**answers

### A specific Schwartz function $f$ on $\mathbb C^2$

**2**

**0**answers

### Decay rate of least eigenvalue of Gram matrices

**1**

**0**answers

### If $H$ is a Hilbert space, is the projective tensor product $E\:\hat\otimes_\pi\:H$ isometrically isomorphic to $E\:\hat\otimes_\pi\:H'$?

**1**

**1**answer

### Does the image of $f$ contain a positive number?

**1**

**1**answer

### Convergence rate of $\operatorname E|\langle X,f_n\rangle|^p$

**1**

**0**answers

### Is there a vector-valued trace such that $\text{tr}((L\otimes_π\text{id}_H)T)=LT$ for all $L∈\mathfrak L(H,\mathfrak L(H))$ and $T∈H\hat\otimes_πH$?

**2**

**1**answer

### Strongly continuous semigroup: continuous or continuous componentwise?

**7**

**0**answers

### Models for Eilenberg-MacLane space K(Z,3)

**0**

**0**answers

### Lie algebra of zero trace trace class operators

**1**

**0**answers

### If $f$ takes values in $L(H,L(H,\Bbb R))$ and $μ$ is a $H\hat ⊗_πH$-valued measure, how are $\int f\:dμ$ and $\int f⊗_π\text{id}_Hdμ$ related?

**6**

**2**answers

### A characterization of metric spaces admitting a bi-Lipschitz embedding into a Hilbert space?

**13**

**1**answer

### A reference to a characterization of metric spaces admitting an isometric embedding into a Hilbert space

**7**

**1**answer

### Flows in Hilbert spaces

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**1**answer

### For $B=\int \lambda d E_\lambda $ and $X$ commutes with every $E_\lambda $, why $BX$ is positive and self-adjoint?

**2**

**1**answer

### The closure of span of a linearly independent and convergent sequence in $\ell^2$ [closed]

**3**

**1**answer

### Can the $L^{\infty}\to L^{\infty}$ norm be bounded by the trace norm?

**1**

**1**answer

### What are examples of a second order operational tangent vector on an infinite dimensional Hilbert space

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**1**answer

### When $\lambda$-commutativity implies commutativity?

**3**

**0**answers