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seen Nov 24 at 14:24

Mar
14
revised Why is $H_1 \le G \land H_2 \le G$ necessary in $a(H_1 \cap H_2) = aH_1 \cap aH_2$?
fixed some typos in formulas
Mar
14
answered Why is $H_1 \le G \land H_2 \le G$ necessary in $a(H_1 \cap H_2) = aH_1 \cap aH_2$?
Mar
8
revised Natural transformations in $\textbf{Set}$
added full citation, with hyperlink
Mar
8
revised Natural uses for the co-product of sets?
added 12 characters in body
Mar
8
revised Natural uses for the co-product of sets?
added 12 characters in body
Mar
8
revised Natural uses for the co-product of sets?
added 1546 characters in body
Mar
7
comment Natural uses for the co-product of sets?
@Rahul: and my contention is that the essential feature of the co-product is that it is a union of disjoint sets (tagged or not), and therefore the issue of tags is a red-herring. I understood Martin Brandenburg's $\mathrm{Humans} = \mathrm{Men} \sqcup \mathrm{Women}$ as saying that the sets $\mathrm{Men}$ and $\mathrm{Women}$ are indeed disjoint, and that their (standard set) union equals the set $\mathrm{Humans}$. Quibbling over how well these assertions represent the real world is like quibbling over whether cows are really spherical.
Mar
7
revised Natural uses for the co-product of sets?
added 195 characters in body
Mar
7
revised Natural uses for the co-product of sets?
edited body
Mar
7
revised Natural uses for the co-product of sets?
edited tags
Mar
7
revised Natural uses for the co-product of sets?
deleted 4 characters in body
Mar
7
revised Natural uses for the co-product of sets?
deleted 4 characters in body
Mar
7
revised Natural uses for the co-product of sets?
added 282 characters in body
Mar
7
revised Natural uses for the co-product of sets?
added 282 characters in body
Mar
7
revised Natural uses for the co-product of sets?
deleted 5 characters in body
Mar
7
revised Natural uses for the co-product of sets?
added 303 characters in body
Mar
7
comment Natural uses for the co-product of sets?
@MJD: I think that tagging may be an inessential "implementation detail", an artifact of adopting a "synthetic", as opposed to an "analytic", point of view; I've written at length about this in an "Epilogue" to my original question.
Mar
7
revised Natural uses for the co-product of sets?
added 4744 characters in body
Mar
7
revised Natural uses for the co-product of sets?
added 4744 characters in body
Mar
3
accepted Natural uses for the co-product of sets?