Some confusion regarding nomenclature

[Matterwave]

Hi guys, I often see the terms: "Outer product", "tensor product", "direct product", and "dyadic product" sometimes used interchangeably...do these 4 terms all mean the same thing, or were they all developed in different fields and some people refer to some as one thing and some as another thing or what? The definition I usually see related to these terms is the creation of a tensor from the product of two vectors. I have heard the terms like this: in Quantum Mechanics when we have a composite state, we take the "tensor product" of two individual states which live in different Hilbert Spaces, in the E.M. Energy Stress Tensor, the Maxwell stress tensor involves the "dyadic product" of the Electric field with itself, etc. What's the deal?

 

[zhermes]

I'm unfamiliar with the direct product, but these explain the relations between the rest...
http://en.wikipedia.org/wiki/Outer_product"
http://en.wikipedia.org/wiki/Tensor_product"
http://en.wikipedia.org/wiki/Dyadic_product"
If these are unclear, please ask a specific question.