Gabriel Dos Reis <[EMAIL PROTECTED]> writes:
> | Gaby, after some experiments, I could not find an example where "A add B", A
> | and B sharing representation, exports an operation from A instead of from B,
> | when the signature is present in both.
>
> That is basically what my oiriginal example was about --
Sorry, I don't understand. In the example below, the representations differ -
IndexedDirectProductAbelianGroup(R,S) is (I'd say) different from List
Pair(S,R).
I wonder whether this strange behaviour also occurs when the representations
are the same.
What do you mean with
> you just needed to flip the component to match exact layout. I'm reproducing
> it below
??? Are you saying that List Pair(S, R) is the same as
IndexedDirectProductAbelianGroup(R,S)?
Martin
> )sys cat left.spad
> )abbrev domain LFREEMOD LeftFreeModule
> LeftFreeModule(R: Ring, S: OrderedSet):
> Join(LeftModule R, IndexedDirectProductCategory(R,S)) with
> linearCombination: List Pair(S,R) -> %
> == IndexedDirectProductAbelianGroup(R,S) add
> Rep == List Pair(S,R)
> linearCombination x ==
> per [u for u in x | second u ~= 0$R ]
> if R has EntireRing then
> (r: R) * (x: %) ==
> r = 0$R => 0$%
> r = 1$R => x
> messagePrint("from LeftFreeModule")$OutputForm
> per [pair(first u, r * second u) for u in rep x]
> else
> (r: R) * (x: %) ==
> r = 0$R => 0$%
> r = 1$R => x
> messagePrint("from LeftFreeModule")$OutputForm
> per [pair(first u,c) for u in rep x | (c := r *second u) ~= 0$R]
> coerce(x: %): OutputForm ==
> x' := rep x
> null x' => 0$R :: OutputForm
> res : List OutputForm := nil
> for u in reverse x' repeat
> second u = 1$R => res := cons(first(u)::OutputForm, res)
> res := cons(second(u)::OutputForm * first(u)::OutputForm, res)
> reduce("+",res)
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