X and Y are sets. X is infinity and Y is countable. How can I show that #X=#(XUY)
23442
Cardinality of the union of infinite and countable sets
120273
Showing that a collection of sets is a $\sigma$-algebra: either set or complement is countable
108922
Cardinality and infinite sets: naturals, integers, rationals, bijections
117478
Prove that $\mathbb{R}$ and the interval $(0, \infty)$ have the same cardinality.
91163
Let the set S be infinite, and the set T countably infinite. Show that S and S U T have the same cardinality
111008
Show that $X $ is a infinite set ,it is connected in the finite complement topology?
99656
Prove that the set of all algebraic numbers is countable
41192
Neatest proof that set of finite subsets is countable?
141227
How to show the integers have same cardinality as the natural numbers?
34998
How to prove that $\mathbb{Q}$ ( the rationals) is a countable set
98151
Suppose that A is a countable set. Show that the set B is also countable if there is an onto function f from A to B.
145873
Let $X$ and $Y$ be finite sets. Then the set $Y^X$ is finite and $\#(Y^X) = (\#Y)^{\#X}$.
79490
Proving the set of points at which a function diverges to $\infty$ is countable
134071
If A is a finite set and B is an infinite set, then B\A is an infinite set
120562
If A is an infinite set and B is at most countable set, prove that A and $A \cup B$ have the same cardinality
75019
Infinite Cartesian product of countable sets is uncountable
102113
Proof that the number of proofs is countably infinite