Missing multiplication symbol

2021-07-16T09:11:05Z

IJK123: +1

[[Category:Ambiguities]]

It's common to omit a multiplication symbol:

\(ab = a \times b\)

But sometimes it's not as clear:

Does \( a(b+1) = a \times (b+1)\), or is \(a\) a function?<ref>[https://twitter.com/christianp/status/798843905231888385 Tweet by Christian Lawson-Perfect]</ref>

When writing a division on one line, does an implied multiplication bind more tightly than an explicit one?<ref>[https://twitter.com/christianp/status/1320650593241866241 Twitter thread by Christian Lawson-Perfect]</ref>

Is \(a/bc\) equivalent to \(\frac{a}{bc}\) or \(\frac{a}{b}c\)?

There seems to be an unwritten rule "juxtaposition is stickier".

But that might not apply when there are numbers involved: almost everyone would interpret \(2/3x\) as \(\frac{2}{3}x\) instead of \(\frac{2}{3x}\)

The "juxtaposition is stickier" rule only seems to break ties, not override the normal [[order of operations]]:

\[ ab^2 = a \times (b^2) \]

Sometimes the ambiguity comes from mistaking a function for an operation:

\[ (a+b) \Phi (a+b)\]

which can be viewed as either \( (a+b)\cdot \Phi(a+b)\), or \(\Phi\) as binary addition-like operation, similar to \( (a+b)\oplus (a+b)\).<ref>Igor Pak, [https://scholarship.claremont.edu/jhm/vol8/iss1/14/ How to Write a Clear Math Paper: Some 21st Century Tips]</ref>
==References==
<references/>

Why start at x, y, z - User contributions [en-gb]

Missing multiplication symbol