While you are right that De Morgan's law is part of logic, I consider logic to be part of Math. This might be a slightly contentious claim, but I know a few logicians who agree with me about this. Plus you can prove some nifty isomorphisms between abelian algebras and various logics.
But I have a fairly wide view of what qualifies as Math...
Computer science is merely the post-Turing decline of formal systems theory.
Symbolic logic is no more a subset of Mathematics than it is a subset of Philosophy. Symbolic logic is a discipline unto itself. There are several different symbolic logics, most convertible one to the other.
And, symbolic logic is not the sole necessity to be a good programmer, but more on that in the main thread.
------ We are the carpenters and bricklayers of the Information Age.
The idea is a little like C++ templates, except not quite so brain-meltingly complicated. -- TheDamian, Exegesis 6
Please remember that I'm crufty and crochety. All opinions are purely mine and all code is untested, unless otherwise specified.