It is possible in certain ways, if you have enough time to write. For example, you can invent a complex problem, spend a very long time figuring out your solution, then have that solution occur to your character very quickly. This can be done with very concrete problems, such as with mathematical or physical principles, and also with more abstract reasoning such as “how do I design a trap that can kill a dragon, then trick the dragon into falling for it.”
However, you are correct that one can never write a character that is smarter than the author(s) in that he will conceive of something they never could.
It is possible in certain ways, if you have enough time to write. For example, you can invent a complex problem, spend a very long time figuring out your solution, then have that solution occur to your character very quickly. This can be done with very concrete problems, such as with mathematical or physical principles, and also with more abstract reasoning such as “how do I design a trap that can kill a dragon, then trick the dragon into falling for it.”
However, you are correct that one can never write a character that is smarter than the author(s) in that he will conceive of something they never could.