Identity Flashcards
1
Q
Everything is identical with something.
A
x=x
2
Q
Nothing is distinct from itself.
A
x=x
3
Q
Everything differs from something.
A
(x)(∃y)~x=y
4
Q
Nothing differs from everything.
A
~(∃x)(y)~x=y
5
Q
Each thing is identical with itself.
A
(x)x=x
6
Q
If two things are identical to a third thing, then they are identical to each other.
A
(x)(y)(z)[(x=z∙y=z)→x=y]
7
Q
At least two people invented the airplane.
A
(∃x)(∃y)[((Px∙Py)∙(Ax∙Ay))∙~x=y]
8
Q
Only Faraday discovered electromagnetic induction.
A
Df∙(x)(Dx→x=f)
9
Q
Goliath is the tallest human.
A
Hg∙(x)((Hx∙~x=g)→Tgx)
10
Q
At most two persons invented the airplane.
A
(x)(y)(z)[((Px∙Ax)∙(Py∙Ay))∙(Pz∙Az)]→[(x=y∨x=z)∨y=z])]
