Re: Re: Ansatz?

*To*: mathgroup at smc.vnet.net*Subject*: [mg101091] Re: [mg101071] Re: Ansatz?*From*: Andrzej Kozlowski <akoz at mimuw.edu.pl>*Date*: Wed, 24 Jun 2009 06:28:45 -0400 (EDT)*References*: <h1nf0q$91h$1@smc.vnet.net> <200906231106.HAA08181@smc.vnet.net>

On 23 Jun 2009, at 20:06, M.Roellig wrote: > So, to assume something without any prior derivation could be an > ansatz, but > usually an ansatz would be based on some reasonable assumptions or > additional > knowledge, so "not based on ANY underlying theory or principle" sounds > too > much like a crystal ball. Actually, in almost all cases known to me "Ansatz" refers to a principle or a form of a solution that is known to work but at the stage when it is introduced it is magically "pulled out of a hat" (like a rabbit) without any justification except that the magicians knowledge that it will give the right answer. I wrote in almost all cases, because in pure mathematics ansatz sometimes refers to a method of solving certain kind of problems that has actually been proved; in other words, it's a kind of theorem. One example that comes to my mind is the so called Sinai-Chemov Ansatz in ergodic theory of billiards. Andrzej Kozlowski

**References**:**Re: Ansatz?***From:*"M.Roellig" <markus.roellig@googlemail.com>