Editing Entropy (information theory) (section)

==Notes==
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<ref name=Note01>This definition allows events with probability 0, resulting in the undefined <math>\log(0)</math>. We do see <math>\lim\limits_{x\rightarrow0}x\log(x)=0</math> and it can be assumed that <math>0\log(0)</math> equals 0 in this context. Alternatively one can define <math>p\colon \mathcal{X}\to(0, 1]</math>, not allowing events with probability equal to exactly 0.</ref>

<ref name=Note02>This use of ''unity'' is ambiguous. The original paper ''"A Mathematical Theory of Communication"'' from 1948, mentions ''unity'' in a footnote saying: "In mathematical terminology the functions belong to a measure space whose total measure is unity". In the 1998 reprint ''"The Mathematical Theory of Communication"'', Weaver applied the term ''unity'' in two different instances. On page 9: ''"[...] the information, when there are only two choices, is proportional to the logarithm of 2 to the base 2. But this is unity; so that a two-choice situation is characterized by information of unity [...]. This unit of information is called a 'bit'"''. On page 15: ''"In the limiting case where one probability is unity (certainty) and all the others zero (impossibility), then H is zero"'', which seems in direct contrast to what was stated earlier.</ref>
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