Could you please help me out with this little issue, I need to know how to prove the following assertion. I'll be very thankful for your efforts :) Thanks in advance,
$$\exists !xP(x) \equiv \exists x(P(x) \land \forall y(P(y) \rightarrow y=x))$$
Could you please help me out with this little issue, I need to know how to prove the following assertion. I'll be very thankful for your efforts :) Thanks in advance,
$$\exists !xP(x) \equiv \exists x(P(x) \land \forall y(P(y) \rightarrow y=x))$$