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Re: The orde of product

  • To: mathgroup at smc.vnet.net
  • Subject: [mg123438] Re: The orde of product
  • From: "Chris Degnen" <degnen at cwgsy.net>
  • Date: Wed, 7 Dec 2011 06:15:29 -0500 (EST)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com

Hi,

This includes the reverse process:

SameQ[a*b,b*a]
Unprotect[Times];
Attributes[Times]=DeleteCases[Attributes[Times],Orderless];
Protect[Times];
SameQ[a*b,b*a]
Unprotect[Times];
Attributes[Times]=Append[Attributes[Times],Orderless];
Protect[Times];
SameQ[a*b,b*a]

But I think you should probably use Bob Hanlon's suggestion of NonCommutativeMultiply (**), i.e.

SameQ[a*b,b*a]
SameQ[a**b,b**a]


  ----- Original Message -----
  From: Happ
  To: Chris Degnen ; mathgroup
  Sent: Wednesday, December 07, 2011 2:31 AM
  Subject: =BB=D8=B8=B4=A3=BA The orde of product


  Thank you very much!

  What you have done is really what I want.

  Besides this, I also want to know how can I get back to the original definition of "*" by Mathematica 7.

  Can you help me?

  ------------------
  =C9=D0=C1=C1
  =D3=DA



  ------------------ =D4=AD=CA=BC=D3=CA=BC=FE ------------------
  =B7=A2=BC=FE=C8=CB: "Chris Degnen";
  =B7=A2=CB=CD=CA=B1=BC=E4: 2011=C4=EA12=D4=C27=C8=D5(=D0=C7=C6=DA=C8=FD) =
=C9=CF=CE=E77:25
  =CA=D5=BC=FE=C8=CB: "mathgroup"; "=B5=C0 =BA=F1";
  =D6=F7=CC=E2: Re: The orde of product

  I'm pretty sure this isn't what you want:

  SameQ[a*b, b*a]
  Unprotect[Times];
  Attributes[Times] == DeleteCases[Attributes[Times], Orderless];
  Protect[Times];
  SameQ[a*b, b*a]


  =B5=C0 =BA=F1 wrote:
  >
  > How can I do that a*b is unequal to b*a in Mathematica 7?
  > Thank you.
  >


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