We often think of Mathematics as the art and science of manipulating numbers. This is not entirely wrong but is still quite a limited view.
1 + 1 = 2
⬆this is how mathematics and computation looked many centuries ago
This is modern mathematics:
More recently mathematics is about big abstract ideas and then trying to make them useful in the real world (which is desirable but not always possible). The abstract space of mathematics is conceptually larger than anything else we know and only minuscule parts of it find applications in practice. We often find uses for very abstract theories only after long time has passed since initial discoveries.
One of the big ideas of mathematics is the notion of computation. Please note that computation ≠ calculation.
Calculation is understood as applying basic operations to numbers.
Computation is all about continuously and reliably manipulating state to achieve the appropriate output / behaviour of the computing system.
Here is one prominent way of describing computation — a State Machine:
Please read this quote from the 2008 paper by Leslie Lamport:
I have tried to show that state machines provide a simple conceptual framework for describing computation.
The advantage of state machines is that they can be described using ordinary mathematics. Mathematics is simpler and more expressive than any language I know that computer scientists have devised to describe computations. It is the basis of all other branches of science and engineering. Mathematics should provide the foundation for computer science as well.
I hope that with this explanation we can better appreciate how Mathematics and Computation are related but not the same.
Once the all-mightly physics comes into play, we start having real problems and we have to improvise our ways around them as good as Nature allows.
Distributed systems are the intersection of Mathematics, Physics and Computer Science. Is there anything more interesting you can think of? ☺
Conclusion of this short post is that the barriers between Mathematics, Computer Science and Physics are somehow blurry but edges are still visible enough so that we know which is which. It probably takes more than a lifetime to be fully certain though...