How to extend underbrace to another equation line?

Questions
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1

Hello, I have the following equation:

$
  sum_e cal(R)_e^TT (BB_e AA_e^(-1) (SS_e - CC_e cal(R)_e Lambda) + LL_e cal(R)_e Lambda) &= 0 \
  underbrace(sum_e cal(R)_e^TT (LL_e - BB_e AA_e^(-1) CC_e) cal(R)_e, cal(A)) Lambda &= underbrace(-sum_e cal(R)_e^TT BB_e AA_e^(-1) SS_e, cal(B)) \
  cal(A) Lambda &= cal(B)
$

which is rendered like this

image
image488×150 19.8 KB

is there maybe a way to make the underbraces extend to the $cal(A)$ and $cal(B)$ below? Or in general is there a way (not necessarily with the same braces) to typeset this equation in a subjectively nicer way?

Thank you

2

Extend like this?

image
image788×244 28.9 KB

The OP is lacking description of the desired output.

I think the output is already nice. Depending on what you expect.

3

Yes, something along those lines. I don’t think the output is ugly but I really dislike repetitions so I’m looking for opinions on alternative ways to typeset this

4

What repetitions? Typst can’t do such diagonal typesetting in math natively. You would have to probably make a custom solution. Mannot is a really good tool for this. You can of course use rotate and move and stuff like this, but that would be a hard-coded solution that won’t adapt to the math content.

5

By repetitions I mean $cal(A)$ and $cal(B)$. That package looks useful, I’ll take a look, thanks

6

This?

image
image706×227 25.1 KB

That’s…not really a repetition. It’s like saying I don’t like that I have to write x on every line when solving an equation with x variable.

If you mean that 6 chars for 1 visual one is too much, then use let cA = $cal(A)$, or any other alias. Though, 1-letter aliases will have to be preceded by #.

7

More minimalist maybe - I was just thinking what if this was a blackboard, how might you draw it? I can see that it seems like repetition or a bit crowded if you have both the underbrace with A and the A directly below it.

equation
equation767×239 27.5 KB

code 
#import "@preview/mannot:0.3.0": markhl, markul

#let mark1 = markul
#let mark2 = (body, ..args) => markul(markul(body, ..args), outset: (bottom: 2.5pt))
$
  sum_e cal(R)_e^TT (BB_e AA_e^(-1) (SS_e - CC_e cal(R)_e Lambda) + LL_e cal(R)_e Lambda) &= 0 \
  mark1(sum_e cal(R)_e^TT (LL_e - BB_e AA_e^(-1) CC_e) cal(R)_e) Lambda &= mark2(-sum_e cal(R)_e^TT BB_e AA_e^(-1) SS_e) \
  \
  mark1(cal(A)) Lambda &= mark2(cal(B))
$

whether you do this with an underline (markul) or with colors (markhl) depends on the style of the document, colorful highlight fits in certain presentations and textbooks.

1 Like
8

I hadn’t thought of using underlines or highlights for it. I’ll think about it a bit, thanks!