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Re: [Ffc] New syntax for mixed and enriched spaces

 

In favor.

--
Marie

> After Marie's latest addition of enriched spaces (and some discussion
> with Doug Arnold), it seems clear that our current notation V + W for
> mixed spaces is not optimal.
>
> Even though one may think of the operation of creating a "mixed
> function space" as a direct sum,
>
>   X = {(v, 0) : v in V} \oplus {(0, w) : w in W},
>
> it is more natural (and common) to think of it as a Cartesian product,
>
>   X = V \times W = {(v, w) : v in V, w in W}
>
> It would therefore be more natural to use '*' instead of '+' as the
> operation for creating mixed elements/function spaces.
>
> That would free up '+' to be used for enriched spaces (which have
> recently been added),
>
>   X = {v + w : v in V, w in W}
>
> The typical example would be to take V piecewise linears and W scaled
> P3 bubbles.
>
> In summary, the suggestion is to use the following notation:
>
>   +  <-->  +
>   *  <-->  \times
>
> It's obvious this is better than what we have now which is
>
>   +  <--> \oplus
>   ?  <--> +
>
> Thoughts?
>
> --
> Anders
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