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# Testing 3

edited October 2014 in General

A double subscript $$a_{b_c}$$

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1.
edited October 2014

Let's try one with double asterisks: $\int_0^\infty a*b*c dx$

Comment Source:Let's try one with double asterisks: $\int_0^\infty a*b*c dx$
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2.

Without the asterisks we get $\int_0^\infty a b c dx$

Comment Source:Without the asterisks we get $\int_0^\infty a b c dx$
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3.
edited October 2014

That's odd that the MathML version of the first post is not displayed as a block element. What's the code? Presumably $$a_b_c$$. Let's give that a go: $$a_b_c$$

Ah, but it wasn't on a fresh line. $$a_b_c$$ Hmm, I note that MathJaX can't cope with unbraced double subscripts. That is, $a_b_c$ doesn't work in MathJaX: $a_b_c$.

Comment Source:That's odd that the MathML version of the first post is not displayed as a block element. What's the code? Presumably $$a_b_c$$. Let's give that a go: $$a_b_c$$ Ah, but it wasn't on a fresh line. $$a_b_c$$ Hmm, I note that MathJaX can't cope with unbraced double subscripts. That is, $a_b_c$ doesn't work in MathJaX: $a_b_c$.
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4.
edited October 2014

Anyway, back to my second post. Double asterisks don't work in the MathJaX version: $a^* a = \| a^* \|^2$. Now that's odd, that one did work. Let's try something simpler such as $a*b*c$. Right, so that didn't work. I guess the asterisks have to be next to actual letters. Odd that underscores end up in a box so that stars and underscores are treated differently. Hmm, let's try $a _b_ c$.

Whoa! Something weird happened just there! I want to try that last example again: $a _b_ c$.

Okay, so the double underscore works because Markdown deliberately doesn't affect underscores when they are in the middle of a word. That is, in hello_world_greetings then the underscores are not special, but in helloworldgreetings then the asterisks are special.

So in $a_b_c$ then the underscores are passed through to MathJaX because they aren't special in Markdown. But in $a _b_ c$ then they are special in Markdown and so aren't passed through to MathJaX. Ditto with asterisks; they aren't always special in Markdown but when they are then they aren't passed through.

Let's try some other special stuff from Markdown. $a*b*c$.

Comment Source:Anyway, back to my second post. Double asterisks don't work in the MathJaX version: $a^* a = \| a^* \|^2$. Now that's odd, that one did work. Let's try something simpler such as $a*b*c$. Right, so that didn't work. I guess the asterisks have to be next to actual letters. Odd that underscores end up in a box so that stars and underscores are treated differently. Hmm, let's try $a _b_ c$. Whoa! Something weird happened just there! I want to try that last example again: $a _b_ c$. Okay, so the double underscore works because Markdown deliberately doesn't affect underscores when they are in the middle of a word. That is, in hello_world_greetings then the underscores are not special, but in hello*world*greetings then the asterisks are special. So in $a_b_c$ then the underscores are passed through to MathJaX because they aren't special in Markdown. But in $a _b_ c$ then they are special in Markdown and so aren't passed through to MathJaX. Ditto with asterisks; they aren't always special in Markdown but when they are then they aren't passed through. Let's try some other special stuff from Markdown. $a*b*c$.