In interior of the set of positive operators the question is about the topology of $\mathcal{P}(\mathcal{H}):=\{A\in \mathcal{L}(\mathcal{H})\mid \langle Ax,x\rangle \geq 0\}$, namely if the interior is empty, if the ambient space is $\mathcal{L}(\mathcal{H})$ for a Hilbert space $\mathcal{H}$. I was wondering, how a change of ambient space might change the interior. For this, I want to compute $\partial \mathcal{P}(\mathcal{H})$ in $\mathcal{L}_s(\mathcal{H})$, or even better, I want to show, that $\mathcal{F}_s^+(\mathcal{H}):=\{T\in\mathcal{F}(\mathcal{H}):\sigma(T)>0\}$ is in fact the interior of $\mathcal{P}(\mathcal{H})$. One can actually show, that if $0\in T$ for a selfadjoint Fredholm operator $T$, then $T\in \partial \mathcal{P}(\mathcal{H})$, but I fail to show the converse inclusion. Or is there even a counterexample?
2026-02-23 01:22:38.1771809758
Interior of set of positive operators
35 Views Asked by Bumbble Comm https://math.techqa.club/user/bumbble-comm/detail AtRelated Questions in GENERAL-TOPOLOGY
- Is every non-locally compact metric space totally disconnected?
- Let X be a topological space and let A be a subset of X
- Continuity, preimage of an open set of $\mathbb R^2$
- Question on minimizing the infimum distance of a point from a non compact set
- Is hedgehog of countable spininess separable space?
- Nonclosed set in $ \mathbb{R}^2 $
- I cannot understand that $\mathfrak{O} := \{\{\}, \{1\}, \{1, 2\}, \{3\}, \{1, 3\}, \{1, 2, 3\}\}$ is a topology on the set $\{1, 2, 3\}$.
- If for every continuous function $\phi$, the function $\phi \circ f$ is continuous, then $f$ is continuous.
- Defining a homotopy on an annulus
- Triangle inequality for metric space where the metric is angles between vectors
Related Questions in FUNCTIONAL-ANALYSIS
- On sufficient condition for pre-compactness "in measure"(i.e. in Young measure space)
- Why is necessary ask $F$ to be infinite in order to obtain: $ f(v)=0$ for all $ f\in V^* \implies v=0 $
- Prove or disprove the following inequality
- Unbounded linear operator, projection from graph not open
- $\| (I-T)^{-1}|_{\ker(I-T)^\perp} \| \geq 1$ for all compact operator $T$ in an infinite dimensional Hilbert space
- Elementary question on continuity and locally square integrability of a function
- Bijection between $\Delta(A)$ and $\mathrm{Max}(A)$
- Exercise 1.105 of Megginson's "An Introduction to Banach Space Theory"
- Reference request for a lemma on the expected value of Hermitian polynomials of Gaussian random variables.
- If $A$ generates the $C_0$-semigroup $\{T_t;t\ge0\}$, then $Au=f \Rightarrow u=-\int_0^\infty T_t f dt$?
Related Questions in FUNCTIONAL-CALCULUS
- About vectors that have bounded support representation on the spectrum of a self-adjoint operator
- proving existence of a particular linear operator on the space of bounded functions
- How do I prove that the following function is increasing in $t\geq 1$ for any $1\leq y \leq t$?
- Proving that a family of exponential operators has a uniform bound, without semigroup theory.
- Consider the operator $T:L^2(0,1)\rightarrow L^2(0,1)$. Is it well defined, linear, bounded, compact?
- Is this a Functional Differential Equation? How to solve it?
- Holomorphic functional calculus proving a property of fractional powers
- Showing that the Holomorphic Functional Calculus preserves adjoints.
- Compute $\frac{d}{dx(t)}\int_0^Tx(\tau)^TAx(\tau)d\tau$
- If $f \in C(\sigma(a))$ and $g \in C(\sigma(f(a)))$, proof that $(g \circ f)(a) = g(f(a))$
Related Questions in GEOMETRIC-FUNCTIONAL-ANALYSIS
- Bound degrees of sparse random graphs
- How to vary a second order function with respect to the metric tensor?
- About non-separable Hilbert spaces
- Differentiability of Norms of $l_{\infty}$
- Realizing the Berkovich affine line as a union of Berkovich spectrums
- Definition of the Berkovich spectrum
- Distance between two functions in term of a third function
- Prove that $\forall t \in \mathbb R$ the set $f^{-1}(\{t\})$ is a hyperplane of $X$
- Hahn Banach Theorem implying existence of a nonzero linear functional taking 0 in a linear subspace
- Given a "composite" norm, what polygon describes its unit ball?
Trending Questions
- Induction on the number of equations
- How to convince a math teacher of this simple and obvious fact?
- Find $E[XY|Y+Z=1 ]$
- Refuting the Anti-Cantor Cranks
- What are imaginary numbers?
- Determine the adjoint of $\tilde Q(x)$ for $\tilde Q(x)u:=(Qu)(x)$ where $Q:U→L^2(Ω,ℝ^d$ is a Hilbert-Schmidt operator and $U$ is a Hilbert space
- Why does this innovative method of subtraction from a third grader always work?
- How do we know that the number $1$ is not equal to the number $-1$?
- What are the Implications of having VΩ as a model for a theory?
- Defining a Galois Field based on primitive element versus polynomial?
- Can't find the relationship between two columns of numbers. Please Help
- Is computer science a branch of mathematics?
- Is there a bijection of $\mathbb{R}^n$ with itself such that the forward map is connected but the inverse is not?
- Identification of a quadrilateral as a trapezoid, rectangle, or square
- Generator of inertia group in function field extension
Popular # Hahtags
second-order-logic
numerical-methods
puzzle
logic
probability
number-theory
winding-number
real-analysis
integration
calculus
complex-analysis
sequences-and-series
proof-writing
set-theory
functions
homotopy-theory
elementary-number-theory
ordinary-differential-equations
circles
derivatives
game-theory
definite-integrals
elementary-set-theory
limits
multivariable-calculus
geometry
algebraic-number-theory
proof-verification
partial-derivative
algebra-precalculus
Popular Questions
- What is the integral of 1/x?
- How many squares actually ARE in this picture? Is this a trick question with no right answer?
- Is a matrix multiplied with its transpose something special?
- What is the difference between independent and mutually exclusive events?
- Visually stunning math concepts which are easy to explain
- taylor series of $\ln(1+x)$?
- How to tell if a set of vectors spans a space?
- Calculus question taking derivative to find horizontal tangent line
- How to determine if a function is one-to-one?
- Determine if vectors are linearly independent
- What does it mean to have a determinant equal to zero?
- Is this Batman equation for real?
- How to find perpendicular vector to another vector?
- How to find mean and median from histogram
- How many sides does a circle have?