Bill Page wrote:
> 
> On Sat, Nov 10, 2018 at 12:02 PM Waldek Hebisch
> <[email protected]> wrote:
> ...
> >
> > I have now implemented the lift part of Davenport-Caruso method.
> > You fetch code at:
> >
> > http://www.math.uni.wroc.pl/~hebisch/fricas/dcfact2.input
> > http://www.math.uni.wroc.pl/~hebisch/fricas/nc_ini04c.input
> >
> > As before, dcfact2.input is an actual routine, nc_ini04c.input
> > set up needed types.
> 
> This looks very promising however I did find this apparent failure:
> 
> (82) -> h3
> 
>    (82)  - z y x + z x y + y z x - y x z - x z y + x y z
> Type: 
> XDistributedPolynomial(OrderedVariableList([x,y,z,w,x1,x2,x3,x4,x5]),Fraction(Integer))
>                                                    Time: 0.00 (OT) = 0.00 sec
> (83) -> dc_fact((3+x*z*y)*h3)
> 
>    (83)
>    [
>        - 3 z y x + 3 z x y + 3 y z x - 3 y x z - 3 x z y + 3 x y z - x z y z 
> y x
>      +
>                           2           2
>        x z y z x y + x z y z x - x z y x z - x z y x z y + x z y x y z
>      ]
> Type: 
> List(XDistributedPolynomial(OrderedVariableList([x,y,z,w,x1,x2,x3,x4,x5]),Fraction(Integer)))
>                                                    Time: 0.00 (OT) = 0.00 sec
> 

Thanks for testcases (this one and from other post).  I overlooked
a case when lift equation has unique solution, but the simple
method used by 'dc_fact1' found wrong one.  Now those cases
are hanlded like cases with non-unique solution and passed to
'solve' to sort out.  New version at:

http://www.math.uni.wroc.pl/~hebisch/fricas/dcfact3.input

-- 
                              Waldek Hebisch

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