5.532
And analogously: not “(∃x,y).f(x,y).x=y”, but “(∃x).f(x,x)”; and not “(∃x,y).f(x,y).~x=y”, but “(∃x,y).f(x,y)”. (Therefore instead of Russell’s “(∃x,y). f(x,y)”: “(∃x,y).f(x,y).∨.(∃x).f(x,x)”.)
And analogously: not “(∃x,y).f(x,y).x=y”, but “(∃x).f(x,x)”; and not “(∃x,y).f(x,y).~x=y”, but “(∃x,y).f(x,y)”. (Therefore instead of Russell’s “(∃x,y). f(x,y)”: “(∃x,y).f(x,y).∨.(∃x).f(x,x)”.)