erf, as a function C-C, is not 1:1 (see 7.13(i) of DLMF), so this
simplification would be incorrect.
I do not know how to tell Sage that you want real-valued
functions/variables, when of course it would be correct to do the
simplification.
On Friday, 27 December 2013 22:40:40 UTC, Buck
Furthermore, DLMF 7.17 only defines the inverse error function on the real
line (in fact (-1,1))
I do not recall ever seeing a discussion of the complex inverse error
function. Strecok (1968) shows that it satisfies y''=2yy'y',
but this is nonlinear, so the methodology of the paper below doesn't
Thanks.
If I understand you, the problems lie in the complex domain, where I was
only thinking of the real numbers.
Can I not do something to the effect of assume(x, 'real') ?
On Saturday, December 28, 2013 10:07:41 AM UTC-8, JamesHDavenport wrote:
erf, as a function C-C, is not 1:1 (see
Yes, I can, but it doesn't have the intended (or any) effect:
sage: assume(x, 'real')
sage: assume(y, 'real')
sage: assumptions()
[x is real, y is real]
sage: solve(erf(x) == erf(y), x)
[x == inverse_erf(erf(y))]
On Saturday, December 28, 2013 11:27:09 AM UTC-8, Buck Golemon wrote:
Thanks.
I've found here:
http://mathworld.wolfram.com/InverseErf.html
[image: erf^(-1)(erf(x))][image: =][image: x,]
(2)
with the identity holding for [image: x in R]
Is this a bit of information that can be added (by me?) to sage?
On Saturday, December 28, 2013 11:32:02 AM UTC-8, Buck Golemon wrote:
