Does the existence of mathematics depend on the existence of the universe, or does mathematics represent something that could at least conceivably exist independent of any physical reality?
Why or why not?
Math is a useful tool but only works as well as the foundation premises that are used. For example in computer games, the physics engines that allow the characters to fly, take damage, and regenerate are controlled by math.
In this case, the assumptions and premises behind the math are modified so the game play is more exciting. Math is like a faithful horse and will dutifully follow the bidding of the rider. This is why it is very important to make sure foundation premises of science are sound, since the math is not prejudice of any assumption by the rider, even if not fully true.
Here is an interesting example of the power of math. I can use a simple principle of math to prove one the miracles in the bible. The miracle is Jesus feeding the multitude of thousands with just a few fish and a few loaves of bread. All he had to do with divide the fish and bread by a fraction; 1/1000.
One Fish times 1/(1/1000)=1000 fish.
This particulate math operation cannot be demonstrated in reality, unless it is done as a miracle. The mechanics of this operation leaves the realm of reality but it is nevertheless the basis for many important math relations, such as in Special Relativity; Lorentz transform.