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Examples-counterexamples
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Which of the following is a counterexample for the statement
August 16th, 2022
discrete-mathematics
logic
examples-counterexamples
What is an example of a subgroup $H\le S_3$ that is not normal?
August 13th, 2022
group-theory
examples-counterexamples
abstract-algebra
Double sequence, two sequences converge, but to different limits?
February 1st, 2020
sequences-and-series
convergence-divergence
examples-counterexamples
real-analysis
calculus
Tensor product of two irreducible representations is not irreducible
December 12th, 2020
abstract-algebra
examples-counterexamples
group-theory
finite-groups
representation-theory
Does $f(0) = 0 \implies f'(x) = 0$?
August 1st, 2022
derivatives
examples-counterexamples
calculus
Proving/Disproving set identity $(A\cap B)\cup C= A\cap (B\cup C)$
August 1st, 2022
discrete-mathematics
elementary-set-theory
examples-counterexamples
Give a counterexample to show that $(AB)^{-1} \neq A^{-1}B^{-1}$
November 6th, 2020
linear-algebra
examples-counterexamples
matrices
Suppose f : A ---> B and g : B ---> A are functions for which g o f = 1A...
August 1st, 2022
algebra-precalculus
proof-writing
computer-science
examples-counterexamples
Sum of two odd functions is always odd.
October 25th, 2020
examples-counterexamples
functions
Disconnectedness, completeness and compactness.
August 1st, 2022
compactness
connectedness
metric-spaces
examples-counterexamples
Counterexample for ∀x∃y (x=1/y)
August 1st, 2022
discrete-mathematics
examples-counterexamples
Example about the Reduced cost in the Big-M method?
August 1st, 2022
linear-programming
operations-research
examples-counterexamples
Counter Example: If |f| is Riemann integrable, then f is not necessarily integrable
August 1st, 2022
examples-counterexamples
riemann-integration
prove that composition $g$ of $f$ is bijective then $f$ is injective and $g$ is surjective
January 19th, 2020
solution-verification
functions
examples-counterexamples
3x3 matrices examples to meet properties
August 1st, 2022
examples-counterexamples
matrices
Can you conclude that A = B if A, B, and C are sets such that...
August 1st, 2022
discrete-mathematics
elementary-set-theory
examples-counterexamples
propositional-calculus
Find two discontinuous functions whose product is continuous
August 1st, 2022
functions
continuity
examples-counterexamples
notation
real-analysis
Example for associative, commutative operations
August 1st, 2022
examples-counterexamples
Vector field with bounded integral curves
January 23rd, 2020
examples-counterexamples
analysis
ordinary-differential-equations
vector-analysis
A simple example of Lindelöf space.
December 22nd, 2020
general-topology
lindelof-spaces
examples-counterexamples
compactness
Example of graph with specific $\chi (G)$, $\omega (G)$, $\beta (G)$
February 27th, 2020
examples-counterexamples
coloring
graph-theory
Graph connected does not imply $f$ is continuous
August 1st, 2022
limits
real-analysis
analysis
examples-counterexamples
multivariable-calculus
Give an example of a continuous strictly increasing function g:R->R which is...
February 20th, 2020
examples-counterexamples
real-analysis
Show that every compact subspace of a metric space is bounded in that metric and is closed
August 1st, 2022
compactness
general-topology
metric-spaces
examples-counterexamples
Examples of nonlinear transformations with only multiplicative or additive property but not both.
August 1st, 2022
functions
examples-counterexamples
linear-transformations
linear-algebra
Show by means of an example that $\lim_{x \to a} [f(x)g(x)]$ may exist even though neither $\lim_{x \to a} f(x)$ nor $\lim_{x \to a} g(x)$ exists.
August 1st, 2022
examples-counterexamples
calculus
limits
Closed set which does not have open subsets
July 27th, 2020
general-topology
examples-counterexamples
If a subset of a partially ordered set has exactly one minimal element, must that element be a smallest element?
August 1st, 2022
discrete-mathematics
order-theory
relations
examples-counterexamples
Real-valued function of one variable which is continuous on [a,b] and semi-differentiable on [a,b)?
August 1st, 2022
real-analysis
examples-counterexamples
calculus
What is the order of $ab$ in an abelian group?
August 26th, 2020
abelian-groups
examples-counterexamples
group-theory
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