Everyone in Japan will be called Sato by 2531 unless marriage law changed, says professor - eviltoast
Sato will become the only option by 2531, suggests modelling as part of campaign to overturn outdated law requiring spouses to have same surname
    • itslilith@lemmy.blahaj.zoneEnglish
      57·
      8 months ago

      ∀P∈X X lives in Japan : P is named Sato

      using De Morgan’s negation rule this is equivalent to

      ⇔ ∄ P ∈X X lives in Japan : P is not named Sato

      Since X X lives in Japan = ∅ 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.