If s=∅ , T≠∅ then SxT = ∅ . Why?
109219
How do the sets $\emptyset\times B,\ A\ \times \emptyset, \ \emptyset \times \emptyset $ look like?
128255
Empty Strings: Why or when is '' equal to ' '?
3072
If the empty set is a subset of every set, why isn't $\{\emptyset,\{a\}\}=\{\{a\}\}$?
52095
Prove either $G=ST$ or |$G|\geq|S|+|T|$
118824
What is the complement of empty set?
134120
Prove statement with a counter-example: For all sets S, T and V, V ∪ (S ∩ T) = (V ∪ S) ∩ T is false
32180
Why is "$A$ unless $B$" equivalent to $A \lor B$?
101326
My teacher describes absolute value confusingly: $|x|=\pm x,\quad \text{if}\enspace x>0 $.
71653
Why is the Cartesian product of a set $A$ and empty set an empty set?
84609
Unary intersection of the empty set
36721
Is "The empty set is a subset of any set" a convention?
89712
For every set $A$, the empty set is a subset of $A$. The empty set is a set. Therefore, the empty set has a cardinality $\geq 1\ldots$
146891
Why is $\{\emptyset\} \not = \emptyset$?
47562
Confusion in symbol of subset.
92055
In JavaScript, why is "0" equal to false, but when tested by 'if' it is not false by itself?
153551
Is the null set a subset of every set?
7443
Why is empty product defined to be $1$?