Re: LAST^2 CALL for SRFI 113, Sets and Bags

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To: John Cowan <cowan@xxxxxxxxxxxxxxxx>

Subject: Re: LAST^2 CALL for SRFI 113, Sets and Bags

From: Kevin Wortman <kwortman@xxxxxxxxx>

Date: Mon, 25 Aug 2014 23:21:45 -0700

Cc: srfi-113@xxxxxxxxxxxxxxxxx

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In-reply-to: <20140826045621.GB5839@mercury.ccil.org>

References: <20140823025913.GB7234@mercury.ccil.org> <CAD2CXevbRxvoBW52OW4CoZvYfbjfSrkyan_LLYxq8xz8hvaV_A@mail.gmail.com> <20140826045621.GB5839@mercury.ccil.org>

Do you think it should be called bag-power-set rather than bag-power-bag?

I guess I'm inclined to think that the operation is called "powerset" even when it's generalized to multisets/bags. But, the text "The procedures for creating and manipulating bags are the same as those for sets, except that set is replaced by bag in their names" means that bag-power-bag is the more consistent name. Personally I don't have strong feelings either way and this feels a little like bike-shedding. I'm comfortable with either name.

Duplicates are treated like any other elements: the power bag of
{a, a, b} is {{}, {a}, {a}, {b}, {a, a}, {a, b}, {a, b}, {a, a, b}}.
I'm not sure what there is to clarify: can you explain?

That is what I'd expect, but a reader might be forgiven for thinking that a power bag is the same as the power set of the unique elements of the bag. In other words, it might help to clarify that the power bag is a set of bags, not a set of sets.

Best regards,
Kevin Wortman