Arthur

cool, thanks!

@LeakyNun so are you thinking A = C = -B as an example where A and C are dependent but A+B and C+D are independent?

@LeakyNun Ah ok. So B = -A implies A+B is constant and is therefore independent of C+D, thanks

if we have 4 random variables A, B, C, D and we know that A+B and C+D are independent. Does that guarantee that A is independent of C and D?

@Alessandro any ideas gratefully received

@MikeMiller It doesn't seem obvious to me but I am no expert

@Alessandro en.wikipedia.org/wiki/…

@Alessandro follow the link. It has the definition

@MikeMiller even for non-square matrices?

@Alessandro I think that is only for square matrices isn't it?

no comments so far

hi...any linear algebra people in? Is math.stackexchange.com/questions/2032918/… obvious?

@ØrjanJohansen Do you think we have reached the limit of what is possible?

Now that's much better!

if anything is unclear in my question please ping me. I will leave this window open

I feel there is always a risk that a challenge either has a trivial optimal solution or is way too hard so that all the answers are the same. I hope this is somewhere in the middle

it will be interesting to see what people come up with

I mean the ppcg one

the challenge is up in case you were interested

@LeakyNun oh hi

posted.. fingers crossed there is no silly mistake

I am thinking of posting codegolf.meta.stackexchange.com/a/12994/71001 unless anyone has any last minute comments?

and please feel free to comment on it :)

thanks

@Adám makes sense

I'll leave it at least overnight in any case

or all at the start?

@Adám do you get regular comments over that week?

seems some questions get sandboxed and some don't

I am not sure what the norm is

in case someone sees a flaw in it?

should I leave codegolf.meta.stackexchange.com/a/12994/71001 over night before setting the question?

@HyperNeutrino improved (and fixed)n the examples

that would be interesting to know

:)

right

the score is easy to compute from given sets

just give the sets and the score

no.. no proofs needed at all

the lower the score the better

that would be terrible :)

@HyperNeutrino no!!

no problem

I thought you meant my challenge for moment :)

any comments on my challenge gratefully received

hi @Lembik ..thanks for the new challenge!

@EriktheOutgolfer thanks!

@Lembik about to post your question...

@Lembik If you don't want to pose it, may I?

hi