using De Morgan’s negation rule this is equivalent to
⇔ ∄ P ∈X : P is not named Sato
Since X = ∅ is the empty set, such a person P can by definition not exist. Which means, the first statement is true. If no person lives in Japan, that means every person living in Japan is named Sato.
For one, there is no legal requirement that a Japanese partner take the name of their foreign spouse (in fact, it’s basically the exception to the rule that all married couples must have the same surname).
That doesn’t contradict the original statement
But it does though
“Every person in Japan will be called Sato.”
In formal logic, this is equivalent to
“There is no person in Japan not called Sato.”
Since there are no people, no one is not called Sato, and therefore every person is called Sato. Every person is also called Steve. Or Klaus.
Edit: once you take the second part of the headline about the marriage law into account you’re right, my bad -
Uh… No? 🤨
∀P∈X : P is named Sato
using De Morgan’s negation rule this is equivalent to
⇔ ∄ P ∈X : P is not named Sato
Since X = ∅ is the empty set, such a person P can by definition not exist. Which means, the first statement is true. If no person lives in Japan, that means every person living in Japan is named Sato.
Your proof is vacuous and you should feel vacuous!
very much so
I volunteer to marry there, and help avert this catastrophe, even a little bit.
For one, there is no legal requirement that a Japanese partner take the name of their foreign spouse (in fact, it’s basically the exception to the rule that all married couples must have the same surname).