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Can someone please help me out with what it means when a symbol says "max+-" or "min+-"? I'm assuming that there is no difference between "max+-" and "max", but please correct me if I'm wrong. I've never run across this symbol before.

Here is an image of an equation which has the symbol is question:

enter image description here

Thanks for the help!

Brian Tung
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Wubbalubbadubdub
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    This is non-standard notation. I think that the reference which contains the symbol is sure to have a line of explanation for it. – EuYu Dec 15 '16 at 20:02
  • It honestly has no reference to this symbol. The paper is titled 'Central-Upwind Schemes for Two-Layer Shallow Water Equations' by Alexander Kurganov and Guergana Petrova if anyone wants to take a look. It's available for free. – Wubbalubbadubdub Dec 15 '16 at 20:06
  • Okay, I think what it means is something like max(lambda1jPH+, lambda1jPH-, lambda2jPH+, lambda2jPH-, ..., 0). But I'll take any comments anyone has still. – Wubbalubbadubdub Dec 15 '16 at 20:22

1 Answers1

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The best guess I can make is that you have to take the $max$ (in the first equation) over all versions of plus and minus in the $\lambda$s, so $$ \max_\pm\{ \lambda^\pm, \mu^\pm, 0\} $$

is shorthand for $$ \max\{ \lambda^+, \lambda^-, \mu^+, \mu^-, 0\} $$

I checked their papers and they seem to like writing what they're ranging over under the word $max$.

But yeah, it is weird and I've never seen it before.

JonathanZ
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