Is the empty set a topological space?
88205
How can I define a topology on the empty set?
128844
An empty intersection of decreasing sequence of closed sets
74860
Why is the empty set a subset of every set?
51710
Is there an infinite connected topological space such that every space obtained by removing one point from it is totally disconnected?
146891
Why is $\{\emptyset\} \not = \emptyset$?
127900
Interior of closure of open set in topological space
65976
in a topological space only finite subsets are compact sets
130418
Is ${\{\emptyset,\{\emptyset\},\{\{\emptyset\}\},\{\{\{\emptyset\}\}\},...\}} $ a set?
858
Is $\{\emptyset\}$ a subset of $\{\{\emptyset\}\}$?
73353
Is it true that a subset that is closed in a closed subspace of a topological space is closed in the whole space?
152354
Why is an empty set not a terminal object in categories $\mathsf{Top}$ and $\mathsf{Sets}$?
70048
In which topologies do open sets maintain open under countable or arbitrary intersection?
660
Is the empty space really empty?
60053
Does the boundary of an open set have measure zero (in $\mathbb{R}^n$)?
1307
Infimum and supremum of the empty set
27107
intersection of the empty set and vacuous truth
110669
Linear span of the empty set