negation of continuity over a set
33289
Negation of definition of continuity
17223
Continuity of an inverse function.
9320
Extension of continuous function on a closed subset of $\mathbb{R}$
62817
Functions which are Continuous, but not Bicontinuous
18222
Set of continuity points of a real function
154559
For each $x\in X$ there exists a neighborhood of x s.t $A\cap U\neq \emptyset$ for only finitely many $A\in\mathcal{A}$. Show that f is continuous.
130415
Negating quantifiers with brackets
47199
Can $\le$ be used insted of < in the definition of continuity?
118332
proof $f(\overline{A})\subseteq \overline{f(A)} \Leftrightarrow f$ continuous
32402
$(A \implies B) \implies (\neg B \implies \neg A)$?
44574
Continuity of absolute value of a function
119888
Is it possible to convert $\forall$ quantifiers to $\exists$ quantifiers without negation?
62208
If $A$ is a non-empty set, then $A \notin A$
90826
Constructing a subset not in $\mathcal{B}(\mathbb{R})$ explicitly
44522
Subsets of the reals when the Continuum Hypothesis is assumed false
153424
Proof of "continuity from above" and "continuity from below" from the axioms of probability
20706
Non-existence of a Surjective Function from a Set to Its Subsets (Cantor's theorem)