Prop: Empty set is a subset of every set.
136755
Direct proof of empty set being subset of every set
56637
In naive set theory ∅ = {∅} = {{∅}}?
20140
Example of set which contains itself
147136
Subset of a countable set is itself countable
110677
How is an empty set truly "empty"?
158671
Cardinality of a set that consists of all existing cardinalities
88205
How can I define a topology on the empty set?
31376
If null set is an element of a set then will it belongs to set or subset?
111349
Finite automaton that recognizes the empty language $\emptyset$
134999
Writing empty set as union of basis elements for a topology.
124325
Element of, subset of and empty sets
71653
Why is the Cartesian product of a set $A$ and empty set an empty set?
71976
Is every element on a set also a set?
10472
Is every set a subset?
13661
Axiom of Regularity allows for this set be an element of itself
123498
Is "empty set" an element of a set?
131983
Prove that $A \subset B$ if and only if $A \setminus B = \emptyset$