(I'm not a native English speaker) When I meet various compositions of mathematical symbols in a book, I pause some time to read them. Also, I don't know that my way of reading them is correct or not.

For example, there are five mathematical expressions.

  1. $\int_a^b f(x) dx$

  2. $\prod_{\alpha \in J} X_\alpha$

  3. $\sum_{i=1}^\infty \mu(E_i)$

  4. $\bigcup_{x\in U} B_x$

My reading method is

1) Integral from $a$ to $b$ $f(x) dx$

2) Product from alpha in $J$ $X$ sub alpha

3) Sum from $i$ is $1$ to infinity mu $E$ sub $i$

4) Union from $x$ in $U$ $B$ sub $x$

Could you give me some advice on how to read expressions like these?


I'm a native english speaker. I'd read these as

  • Integral from $a$ to $b$ of $f ~ dx$.

  • Product over $\alpha$ in $J$ of $X$ sub $\alpha$.

  • Sum from $i$ equals $1$ to infinity of $\mu$ of $E$ sub $i$.

  • Union over $x$ in $U$ of $B$ sub $x$.

  • $\begingroup$ [+1] or, oftentimes, “. . . of $f$ with respect to $x$” $\ddot\smile$ $\endgroup$ – gen-z ready to perish Apr 18 '18 at 23:23

Native English speaker from the US. I vary some of my verbal math. For example, I may read infinite sums and products like $\sum_{j=1}^\infty a_j$ as "The sum, over $j$, of 'a-j'." I ignore saying "sub" now.

In short sum, multiply, and integrate over indices.

Each person is different and your way is just fine.

  • $\begingroup$ I slightly disagree: OP's "union from" and "product from", when the condition is something like $i \in A$, seems really peculiar to me. (If I were editing a paper, I'd suggest a change when I saw this.) $\endgroup$ – John Hughes Apr 15 '18 at 2:47

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.