Timeline for Simplifying a b = 1 in non-commutative products?
Current License: CC BY-SA 3.0
11 events
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| Oct 5, 2014 at 18:08 | comment | added | Teake Nutma |
@vanabel Sorry, I can't decode your last sentence. In any case, ___ is a BlankNullSequence, which can match zero or more arguments. See e.g. this tutorial for more information.
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| Oct 5, 2014 at 14:01 | comment | added | van abel |
@TeakeNutma So why 1**c/.before___ ** a_?NumericQ ** after___ :> a before ** after output NonCommutativeMultiply[c]? I mean it is weird that here before shall be null, then why before**h return NonCommutativeMultiply[h] then?
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| Oct 5, 2014 at 8:24 | comment | added | Teake Nutma |
@vanabel I was referring to the last step in the simplification chain; your example needs the last two steps. So 1**c is not simplified to c because your genericRule is missing the first two rules that move numeric factors outside of NCM.
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| Oct 5, 2014 at 2:10 | comment | added | van abel | @TeakeNutma May I invite you to take a look at my question? | |
| Oct 5, 2014 at 0:56 | comment | added | van abel |
@TeakeNutma It seems that it is not: when I modify the code as:genericRules = { NonCommutativeMultiply[x_] :> x };, then 1**c//ApplyRules output 1**c rather than c.
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| Oct 4, 2014 at 16:47 | comment | added | Mr.Wizard |
@van By the way to automatically apply this set of rules to output you can set $Post = ApplyRules.
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| Oct 4, 2014 at 15:02 | comment | added | Teake Nutma |
@vanabel That's for the last step in this simplification sequence: a ** b ** c -> 1 ** c -> NonCommutativeMultiply[c] -> c. This is similar to what happens for Times, compare namely the following: Times[1, x] -> Times[x] -> x.
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| Oct 4, 2014 at 15:00 | history | edited | Teake Nutma | CC BY-SA 3.0 |
added 234 characters in body
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| Oct 4, 2014 at 13:03 | vote | accept | van abel | ||
| Oct 4, 2014 at 12:51 | comment | added | van abel |
what's the function of NonCommutativeMultiply[x_] :> x
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| Oct 4, 2014 at 10:38 | history | answered | Teake Nutma | CC BY-SA 3.0 |