Informal discussions allow us to communicate about a topic without that formal attitude that demands completeness and precision. We practically worship completeness and precision and for reasons that make sense in mathematics, but occasionally something a little different might give the push to help your car get back on the road, so to speak.
You have probably seen it before, especially in the class like Geometry where we deal with things that are at the primitive level, meaning they’re so basic we can’t describe them in terms of anything else; we sort of have to talk around them before you can see what they are.
We may have a need to talk about something that didn’t get its own chapter in a math textbook. For example, the notion of constraints is very helpful in some of our discussions. Everyone knows what the word constraint means, but I don’t think your Algebra textbook has a chapter about it.
The notion of Truth by Definition was needed several times, but we haven’t seen other authors discuss is. The idea that Definition belongs in a Set with Axiom–we haven’t seen another author say that although we have found sentences that imply those two kids have the same father.
Vectoreverything 