Re: Replacement Rule with Sqrt in denominator

*To*: mathgroup at smc.vnet.net*Subject*: [mg114473] Re: Replacement Rule with Sqrt in denominator*From*: Richard Fateman <fateman at cs.berkeley.edu>*Date*: Sun, 5 Dec 2010 21:52:16 -0500 (EST)*References*: <ic5igm$44p$1@smc.vnet.net> <ic8ad7$81f$1@smc.vnet.net> <id7t95$lh1$1@smc.vnet.net> <idagbn$js7$1@smc.vnet.net> <idd7s6$ngv$1@smc.vnet.net>

On 12/4/2010 3:15 AM, Roland Franzius wrote: >> >> and the pattern does not match. Maybe you don't want it to match in >> this case, but the problem persists even if you do. Like this pattern: >> >> ((1 + I x)^(a/2)/(1 - I x)^(a/2)) /. {HoldPattern[ >> a_^(b_/c_) d_^(e_/c_)] :> (a^b d^e)^(1/c)} >> >> which fails. > > It seems you have not yet recognized that pattern matching in > Mathematica fails by construction if the symbol name of pattern, here a_ > concides with a symbol in the expression. Uh, no, I think you have it wrong. Sin[a] + Sin[b] /. Sin[a_] -> h[a] is perfectly happy to return h[a]+h[b] Sin[a] + Sin[a + b] /. Sin[a_] -> h[a] is perfectly happy to return h[a]+h[a+b]. ... > > So the alternatives are to write an alternative language ... and possibly implement it in Mathematica... > or to learn > mastering the of use it. The same alternative holds for all of > mathematics. Actually this is obviously not correct, since Mathematica can (and does) change. I don't know if "mathematics" changes, but certainly the language of mathematics evolves. RJF