What are the popular/very useful mathematical models for principles in economics?

[27Thousand]

I have a question for those who are cognisant with the study of economics. I've heard in economic classes they teach all sorts of mathematical models to describe/predict all the "laws" in the field, or at least approximations. I'm trying to hunt down the popular and useful economics mathematical equations (I haven't taken an economics class before, but am very curious about the popular models). For those who are familiar with these economic mathematical models, mind sharing the knowledge with da PhysicsForums buddies?

I like conceptualizing cause-effect systems ideas.

 

[Econrocks]

There are a lot of them, especially in microeconomics. I would suggest Mas-Colell, Whinston, and Green', Microeconomic Theory. It lays out the mathematical justification for the foundations of microeconomic.

For macroeconomics, its a bit more varied, and all depends on what you are looking at and to whom you are talking.

 

[ninar]

Here are some of the basic ones with pretty graphics

Microeconomics:

demand/supply
profit maximization
indifference curves & budget constraint
utility function
Edgeworth's box

Macroeconomics:

the classic macroeconomic model
Keynes: the Keynesian cross, IS-LM, Mundell-Fleming model
intertemportal decisions: Modigliani's life cycle, random walk, labor demand

My teacher's all-time fave: Slutsky's equation! (best name ever)

∂x/∂p=∂h/∂p-x*(∂x/∂Y)

edit: here are a few more, less model-y, intermediate topics. the ones above still depend on math but are meant to be a little more conceptual, the following depend more on mathematical treatment

duality in consumer theory
comparative statics
decisions under uncertainty