I've just discovered that I can vote up answers given to my own questions that I have chosen as the right answer.
Isn't it redundant?
If not, what criteria do I need to consider, to vote up/down, or not to vote the answer I've chosen.
An answer could just solve your problem and leave it at that. It would qualify as a correct answer.
An answer could solve your problem, explain where you went wrong, provide ways to avoid ending up there, link you to external resources, explain the solution, provide alternatives, .....
This would also qualify as a correct answer, but would pretty much force you to up-vote it as well :)
EDIT : The two answers to this question are an excellent example of what I am talking about.
The bottom line is that you decide what criteria you use to upvote. Just for a bit of perspective, here is what I do.
My general criteria for accepting an answer: If I post a question and someone posts an answer that directly solves my problem, I accept. If someone posts an answer that leads me to discover the solution and there are no direct solutions provided, I accept. If there's a tie between two equally good answers, I accept based on timestamp typically.
My general criteria for upvoting an answer: If someone posts an answer that is useful in some meaningful way, I upvote. "Some meaningful way" is somewhat vague, but I generally tend to value posts that either teach me something, or have the potential to teach something to future readers.
Not infrequently I see questions along the lines of a straightforward compiler error, asking something like "what is the right syntax here?" A perfectly valid and accept-worth answer in my view would be to simply provide the correct syntax and nothing more. A much better answer would be to provide not just the syntax but also an explanation of why the syntax is needed, maybe some historical perspective, and insight as to why the original syntax was wrong and the correct syntax was right. In my view the first answer would be worthy of an accept but no upvote (if there are no better answers), whereas the latter would be worthy of an upvote as well.
In this way I don't see the two as 100% redundant, but then again I think I have never accepted an answer and not upvoted it.