I downloaded that book from the physics Napster. It looks like something I should be able to handle, but I need help understanding some of the notation.(adsbygoogle = window.adsbygoogle || []).push({});

"Any set called an index set is assumed to be non-void. Suppose T is an index set and for each t within T, A_{t}is a set.

[inter] A_{t}= {x : if t E T, x E A_{t}}

t E T

= for each t within T, x is an element of A_{t}"

There is also another expression with Union rather than Intersection, which I find more difficult to understand (U A_{t}with tET written below U).

U = there exists t E T with x E A_{t}

What is an index set?

Can someone explain this notation?

What is "t" - a number? a set? What does "there exists t E T with x E A_{t}" mean?

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# Elements of Abstract Algebra

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