Bicategories of spans are characterized as cartesian bicategories in which every comonad has an Eilenberg-Moore object and every left adjoint arrow is comonadic.
Keywords: bicategory, finite products, discrete, comonad, Eilenberg-Moore object
2000 MSC: 18A25
Theory and Applications of Categories,
Vol. 24, 2010,
No. 1, pp 1-24.
http://www.tac.mta.ca/tac/volumes/24/1/24-01.dvi
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http://www.tac.mta.ca/tac/volumes/24/1/24-01.pdf
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