I am looking for canonical examples of functions $f\in H^1(\Omega)$ which are not in $L^\infty(\Omega)$, where $\Omega$ is a bounded closed subset of $\mathbb{R}^N$?
2026-04-25 10:38:14.1777113494
An example for $f\in H^1(\Omega)$ but not in $L^\infty(\Omega)$?
170 Views Asked by Bumbble Comm https://math.techqa.club/user/bumbble-comm/detail At
1
There are 1 best solutions below
Related Questions in SEQUENCES-AND-SERIES
- How to show that $k < m_1+2$?
- Justify an approximation of $\sum_{n=1}^\infty G_n/\binom{\frac{n}{2}+\frac{1}{2}}{\frac{n}{2}}$, where $G_n$ denotes the Gregory coefficients
- Negative Countdown
- Calculating the radius of convergence for $\sum _{n=1}^{\infty}\frac{\left(\sqrt{ n^2+n}-\sqrt{n^2+1}\right)^n}{n^2}z^n$
- Show that the sequence is bounded below 3
- A particular exercise on convergence of recursive sequence
- Proving whether function-series $f_n(x) = \frac{(-1)^nx}n$
- Powers of a simple matrix and Catalan numbers
- Convergence of a rational sequence to a irrational limit
- studying the convergence of a series:
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 LEBESGUE-INTEGRAL
- A sequence of absolutely continuous functions whose derivatives converge to $0$ a.e
- Square Integrable Functions are Measurable?
- Lebesgue measure and limit of the integral.
- Solving an integral by using the Dominated Convergence Theorem.
- Convergence of a seqence under the integral sign
- If $g \in L^1$ and $f_n \to f$ a.e. where $|f_n| \leq 1$, then $g*f_n \to g*f$ uniformly on each compact set.
- Integral with Dirac measure.
- If $u \in \mathscr{L}^1(\lambda^n), v\in \mathscr{L}^\infty (\lambda^n)$, then $u \star v$ is bounded and continuous.
- Proof that $x \mapsto \int |u(x+y)-u(y)|^p \lambda^n(dy)$ is continuous
- a) Compute $T(1_{[\alpha,\beta]})$ for all $0<\alpha <\beta<0$
Related Questions in SOBOLEV-SPACES
- On sufficient condition for pre-compactness "in measure"(i.e. in Young measure space)
- $\mbox{Cap}_p$-measurability
- If $u\in W^{1,p}(\Omega )$ is s.t. $\nabla u=0$ then $u$ is constant a.e.
- Weak formulation of Robin boundary condition problem
- Variational Formulation - inhomogeneous Neumann boundary
- Why the Sobolev space $W^{1,2}(M,N)$ weak-sequencially closed in $W^{1,2}(\mathbb R^K)$?
- Sobolev space $H^s(Q)$ is Hilbert
- Duhamel's principle for heat equation.
- How to define discrete Sobolev dual norm so that it can be computed?
- Weakly sequentially continuous maps
Related Questions in LP-SPACES
- Absolutely continuous functions are dense in $L^1$
- Understanding the essential range
- Problem 1.70 of Megginson's "An Introduction to Banach Space Theory"
- Showing a sequence is in $\ell^1$
- How to conclude that $\ell_\infty$ is not separable from this exercise?
- Calculating the gradient in $L^p$ space when $0<p<1$ and the uderlying set is discrete and finite
- $f_{n} \in L^{p}(X),$ such that $\lVert f_{n}-f_{n+1}\rVert_{p} \leq \frac{1}{n^2}$. Prove $f_{n}$ converges a.e.
- Find a sequence converging in distribution but not weakly
- Elementary use of Hölder inequality
- Identify $\operatorname{co}(\{e_n:n\in\mathbb N\})$ and $\overline{\operatorname{co}}(\{e_n : n\in\mathbb N\})$ in $c_0$ and $\ell^p$
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?
For example when $\Omega$ is $B(0,1)$ you can look for $x \mapsto |x|^{\alpha}$ with $\alpha \le 0$. If the dimension is $N=3$ then one finds that $\alpha =1$ works i.e that $f : x \mapsto \frac{1}{|x|}$ is unbounded but that $f \in H^1 (B(0,1))$.