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problem with constant_coefficient of a form of ExteriorAlgebra
 
  
 
  
 
 
 
 
 
 
    
        
        asked 2 years ago  
 
 daniele gravatar image  
 
 
 
 
    
        
        updated 2 years ago  
 
 
 
 
 
Hi,
I have a problem with ExteriorAlgebra and I do not understand where I am wrong. Let's define an ExteriorAlgebra E with some generators:
 
E.<e1,e2,e3> = ExteriorAlgebra(SR)
 
Take for example e1 and compute
 
e1.interior_product(e1)
 
which gives 1, correctly. If I instead compute
 
(e1.interior_product(e1)).constant_coefficient()
 
this gives 0!
 
It worked correctly until time ago, this behaviour only appear now: so probably I'm missing something that changed recently. I'm using SageMath version 9.7 on CoCalc.
 
Thanks in advance!
 
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The same variable e2 appears 2 times
achrzesz gravatar imageachrzesz (
    
        2 years ago
    )
thanks, corrected!
daniele gravatar imagedaniele (
    
        2 years ago
    )
works for me in sage 10.0.beta3
FrédéricC gravatar imageFrédéricC (
    
        2 years ago
    )
@FrédéricC: thanks for pointing this; actually it works in Sage 9.8 as well (cf. answer below).
eric_g gravatar imageeric_g (
    
        2 years ago
    )
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        answered 2 years ago  
 
 eric_g gravatar image  
 
 
 
 
    
        
        updated 2 years ago  
 
 
 
 
 
I confirm the bug in SageMath 9.7, but it has been corrected in SageMath 9.8:
 
sage: E.<e1,e2,e3> = ExteriorAlgebra(SR)
sage: e1.interior_product(e1)
1
sage: (e1.interior_product(e1)).constant_coefficient()
1
 
So the solution is to install SageMath 9.8 or to select a SageMath 9.8 kernel on CoCalc.
 
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        Asked:  2 years ago  
 
 
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        Last updated: Mar 06 '23 
 
 
 
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