Is there a special name for those metric-spaces or topological spaces in which every non-empty open set is uncountable ?
2026-04-03 15:38:43.1775230723
A special kind of metric-spaces
49 Views Asked by user123733 https://math.techqa.club/user/user123733/detail At
1
There are 1 best solutions below
Related 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 SOFT-QUESTION
- Reciprocal-totient function, in term of the totient function?
- Ordinals and cardinals in ETCS set axiomatic
- Does approximation usually exclude equality?
- Transition from theory of PDEs to applied analysis and industrial problems and models with PDEs
- Online resources for networking and creating new mathematical collaborations
- Random variables in integrals, how to analyze?
- Could anyone give an **example** that a problem that can be solved by creating a new group?
- How do you prevent being lead astray when you're working on a problem that takes months/years?
- Is it impossible to grasp Multivariable Calculus with poor prerequisite from Single variable calculus?
- A definite integral of a rational function: How can this be transformed from trivial to obvious by a change in viewpoint?
Related Questions in DEFINITION
- How are these definitions of continuous relations equivalent?
- If a set is open, does it mean that every point is an interior point?
- What does $a^b$ mean in the definition of a cartesian closed category?
- $\lim_{n\to \infty}\sum_{j=0}^{[n/2]} \frac{1}{n} f\left( \frac{j}{n}\right)$
- Definition of "Normal topological space"
- How to verify $(a,b) = (c,d) \implies a = c \wedge b = d$ naively
- Why wolfram alpha assumed $ x>0$ as a domain of definition for $x^x $?
- Showing $x = x' \implies f(x) = f(x')$
- Inferior limit when t decreases to 0
- Is Hilbert space a Normed Space or a Inner Product Space? Or it have to be both at the same time?
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?
Suggested name „nowhere locally countable“ makes perfect sense since it matches the pattern $\text{nowhere-}φ(X) \iff (∀\text{ open }U ⊆ X): ¬φ(U)$. Note that this is equivalent to shorter „nowhere countable“. This also works for nowhere dense subsets with $A ⊆ X$ pattern $\text{nowhere-}φ(A, X) \iff (∀\text{ open }U ⊆ X): ¬φ(A ∩ U, U)$.
There is also a cardinal invariant of topological spaces $Δ(X) = \min\{\lvert U\rvert: U ⊆ X \text{ open}\}$ called dispersion character and used in resolvability theory. So your condition is equivalent to $Δ(X) > ω$.