On 2010-Aug-04 14:51:21 -0700, Nils Bruin <nbr...@sfu.ca> wrote: >There are other areas of mathematics where "<" gets used for proper >inclusion. A group theorist is going to be very surprised if for two >groups H,G, the expression "H < G" is valid but does not mean "H is a >subgroup of G".
I expect this is primarily due to the restrictions of the ASCII character set. More appropriate set comparison and manipulation characters were defined about 50 years ago in APL: ∩ ∪ ⊂ ⊃ ⊆ ⊇ (For those without appropriate glyphs available, these are Unicode codepoints U+2289, U+228A, U+2282, U+2283, U+2286 and U+2287) -- Peter Jeremy
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