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Subject: Re: [boost] Boost.Test updates in trunk: need for (mini) review?
From: Ian Emmons (iemmons_at_[hidden])
Date: 2012-10-29 11:22:13


On Oct 29, 2012, at 6:12 AM, Thorsten Ottosen wrote:
> On 28-10-2012 17:36, Jan Hudec wrote:
>>> From what's written here, it's hard to know whether "cross product" is
>>> wrong or not, but given the number of samples cited, I'm inclined to
>>> believe it's probably right. What result other than the cross product
>>> do you think that means?
>>
>> Any operation that is written with × is called cross product. However
>> that symbol is used for different operations in different contexts. Best
>> known are two meanings, the "vector product" used in physics and "cartesian
>> product" used in set theory and relational algebra.
>>
>> The kind of product we have here, set of tuples where first member is member
>> of first operand and second member is member of second operand, is
>> unambiguously called "cartesian product".
>>
>> So I would probably call it "cartesian product", but "cross product" would
>> not be incorrect.
>
> +1 for Cartesian product. For me at least, "cross product" sounded very confusing.

My apologies -- I meant to say "Cartesian", not "cross". Database people do use the latter to mean the former, but it's ambiguous and clearly a violation of my desire to choose names carefully.


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