Timeline for What justifies this calculation of the derivative of a matrix function?

11 events

when toggle format	what		by	license	comment
Jul 6, 2022 at 16:41	answer	added	zzzhhh		timeline score: 0
Jan 24, 2017 at 4:36	vote	accept	MoneyBall
Jan 23, 2017 at 0:47	history	tweeted			twitter.com/StackStats/status/823331399474221056
Jan 22, 2017 at 23:37	comment	added	Brian Borchers		Between the second and third line he's let $f(A)=AB$. Between the second and third line he's used the product rule. later he uses the chain rule to get rid of $f()$.
Jan 22, 2017 at 21:34	history	edited	whuber♦	CC BY-SA 3.0	edited tags; edited title
Jan 22, 2017 at 21:13	answer	added	whuber♦		timeline score: 22
Jan 22, 2017 at 17:18	history	edited	MoneyBall	CC BY-SA 3.0	created next line
Jan 22, 2017 at 17:18	comment	added	MoneyBall		@whuber I see. Given the assumptions, I still don't understand how the transition happened from second to third line where he introduces $\circ$.
Jan 22, 2017 at 17:07	comment	added	whuber♦		He must be making special assumptions about the dimensions of $A$, $B$, and $C$, for otherwise this formula makes no sense in general. On the left hand side $A$ must be an $i\times j$ matrix, $B$ a $j\times j$ matrix, and $C$ an $i\times m$ matrix for arbitrary non-negative integers $i,j,m$. But then the products on the right would not be defined unless $i=m$.
Jan 22, 2017 at 16:49	history	edited	MoneyBall	CC BY-SA 3.0	deleted 156 characters in body
Jan 22, 2017 at 16:43	history	asked	MoneyBall	CC BY-SA 3.0