FOM: Re: constructive mathematics

Fred Richman richman at
Sun May 28 14:31:31 EDT 2000

Jeffrey Ketland mentions 'a mysterious character called "Sign"' in
Heyting's "Intuitionism, an introduction". I had understood that to
refer to "significs", a philosophy (?) which I know nothing about, but
which was apparently a movement that Brouwer had some involvement
with. See, for example, van Stigt's article "L.E.J. Brouwer, the
signific interlude" in the L. E. J. Brouwer Centenary Symposium
(Noordwijkerhout, 1981), 505--512, Stud. Logic Found. Math., 110,
1982, MR 85d:01026.


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