5.441
This disappearance of the apparent logical constants also occurs if “~(∃x).~fx” says the same as “(x).fx”, or “(∃x).fx.x=a” the same as “fa”.
This disappearance of the apparent logical constants also occurs if “~(∃x).~fx” says the same as “(x).fx”, or “(∃x).fx.x=a” the same as “fa”.