# Notation to Replace the Input to a Function

On pg. 54 of a Quantum Computing textbook (Nielsen and Chuang), it's said that:

it is not surprising that similar techniques can be used to compress the source so that only $$H(p, 1 − p)$$ qubits are required to store the compressed source, where $$H(·)$$ is again the Shannon entropy function.

I'm confused with the use of the symbol "·" and I wonder what's the name of it as how it's used.

• It's showing the name of the function $H$. Oct 13 at 22:01
• @SeanRoberson Thank you for the reply! Howerver, may I ask what does the name of a function mean? Is it the input, ie, what's in the brackets? Oct 13 at 22:23
• It's a placeholder. Nothing too big to worry about. Oct 13 at 22:26