Limit definition and infinitely often

[adnaps1]

Limit definition and "infinitely often"

If we have a sequence of real numbers x_{n} converging to x, that means \forall \epsilon > 0, \exists N such that |x_n - x| < \epsilon, \forall n \geq N.

So, can we say P (|x_n - x| < \epsilon \ i.o.) = 1 because for n \geq N, |x_n - x| < \epsilon always holds?

 

[Stephen Tashi]

So, can we say P (|x_n - x| < \epsilon \ i.o.) = 1

Is that notation suppose to denote a probability? It doesn't define a probability until you establish a scenario that specifies at least one random variable and its probability distribution. Are you thinking of "picking an x_i at random"? Or did you mean the x_i to be a sequence of real valued random variables instead of a sequence of real numbers? (If the x_i are random variables, you have to use a different definition of limit than the one you gave.)

 

[adnaps1]

Yes, the notation P(\cdot) was supposed to denote a probability, and I want the x_i to be a sequence of real numbers, not random variables. But I understand what you're saying. I cannot talk about probabilities without having a random variable.