Given a set and an element, can we say that the element is subset of the given set?
44160
Set theory: difference between belong/contained and includes/subset?
3392
Sum of products of elements of nonempty subsets of A set
20140
Example of set which contains itself
144181
Given an arbitrary set $X$, can one always find an element outside $X$?
49143
Showing $A \subset B \iff A\cap B=A$
29314
Check whether an array is a subset of another
55023
if $A$ subset of $B$ then $P(B)-P(A)=P(B\setminus A)\ge 0$
6679
Counting number of subsets which contain a specific element
3148
True or false: {{∅}} ⊂ {∅,{∅}}
158671
Cardinality of a set that consists of all existing cardinalities
144360
For any sets $A$ and $B$, show that $(B\smallsetminus A)\cup A=B \iff A\subseteq B$.
56637
In naive set theory ∅ = {∅} = {{∅}}?
134914
Let $A,B$ and $U$ be sets so that $A\subseteq U$ and $B\subseteq U$. Prove that $A\subseteq B$ iff $(U\setminus B)\subseteq(U\setminus A)$.
134770
For sets $A,B$, $A \cap (B \setminus A) \subseteq \varnothing$
7462
If X and Y are two sets of vectors in a vector space V, and if X $\subset$ Y, then is span X $\subset$ span Y?
66948
Proving question on sets
76405
Let n be an even integer. How many different ways can I choose subsets of the set {1,2...,n}