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Should I say:

Geodesic Active Contours (GAC) are a method for shape approximation that have demonstrated excellent performance for abdominal wall segmentation.


Geodesic Active Contours (GAC) is a method for shape approximation that has demonstrated excellent performance for abdominal wall segmentation.

Thank you!

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The first one doesn’t agree even with itself: “a method that have demonstrated” is not grammatical. – tchrist Aug 11 '14 at 3:29
The abbreviation in parentheses shows the phrase "Geodesic Active Contours" as a term for a modeling technique. Hence singular. The 'contours' themselves are not the topic here, but the method is. Use the singular. "The technique is based on active contours evolving in time according to intrinsic geometric measures of the image." ( dl.acm.org/citation.cfm?id=250495 ) – Kris Aug 11 '14 at 6:23
up vote 0 down vote accepted

Looking at the way Wikipedia users describe Active Contours, it would seem this is a mass noun that is recognized in the singular form. If you wanted to be extremely explicit, you could write:

The Geodesic Active Contours (GAC) model is a method for shape approximation that has demonstrated excellent performance for abdominal wall segmentation.

In this rewording, it is clear that model and method maintain continuity in the singular form.

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It's not a mass noun. It's a name. You'd say "The Incredibles is a great movie", but that doesn't make The Incredibles a mass noun. – Peter Shor Aug 11 '14 at 3:56
In linguistics, a mass noun or uncountable noun is a noun with the syntactic property that any quantity of it is treated as an undifferentiated unit, rather than as something with discrete subsets. Correct me if I'm wrong, but it does not sound like one could say "One Geodesic Active Contour model, two Geodesic Active Contours models". – ObiWanShanobi Aug 11 '14 at 3:58
Are there quantities associated with an Active Contour model? Can you have a fraction of an Active Contour model? It's not a mass noun, it's a name. – Peter Shor Aug 11 '14 at 4:02
I agree with @PeterShor. You've managed to get the right result (singular verb, and a good re-write) for the wrong reason. I think that makes this answer "not useful", I'm afraid, because it can't be applied to other similar situations where a plural noun like "mathematics" would take a singular verb. – Andrew Leach Aug 11 '14 at 7:07

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