Question to the summation of Grandi's series

20 Views Asked by At

Hello I'm new to this forum.

I've looked at Grandi's series:

S = 1 - 1 + 1 - 1 + 1 ...

If you add brackets, you can get two different result:

S = (1 - 1) + (1 - 1) + (1 - 1) + ... = 0

S = 1 + (-1 + 1) + (-1 + 1) + (-1 + 1) + ... = 1

and you can also derive the equation:

1 - S = S

My question is, instead of saying S = 0.5, can't simply say S is either one or zero depending on context (S = <0|1>)?

You could still solve the equation 1 - S = S:

1 - S1<0|1> = S2<0|1>

If you choose a value for one instance of S the other instance gets fixed:

S1 = 0 -> S2 = 1: 1 - 0 = 1

S1 = 1 -> S2 = 0: 1 - 1 = 0