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An example of what I am trying to understand is found on this page, at Eq. 3.

There are two braces under the equation... What is the definition of the brace(s) and how does it relate to Sp(t) and S[k]? This is what 4 years of calculus gets you 20+ years later...


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up vote 0 down vote accepted

it is a shortcut to let you know that the expression above is equal to it (either by definition or by calculation)

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