Hello, Some have defended conventionalism in mathematics. I shown that hard to sustain in recursion/computability theory, and thus arithmetic. Here something which shows that it is hard to maintain conventionalism in the study of finite symmetries.
Groups (mainly set of symmetries) can be decomposed into some composition of “prime groups” (called simple group). Who is the guy who decided that a all finite simple groups belong to either 18 infinite families of groups, except for 26 exceptional one, the sporadic groups, which does not, and who decided conventionally that the biggest one is Monstruously big, the Monster, which has 808,017,424,794,512,875,886,459,904,961,710,757,005,754,368,000,000,000 elements. All groups can be represented by a group of matrices, with the coefficients belonging to some field (usually the complex numbers), with the usual product of matrice. A field is itself a special sort of double group. (Not to confuse with quantum field, of filed of forces). The minimal dimension needed for that representation is the dimension of the group. It is dimension of the space in which the element of the group represent the symmetries. The Monster group has dimension 196,883 with the matrix coefficient taken in the field of complex numbers, but it has dimension 196.882 on the field z_2 with two elements {0, 1}. Who decided that the dimension of the monster group is 196.882. Divine convention? Could a God makes this in another way? It might play some role in physics, notably conformal fields, strings,… (cf Munshine). A rather nice video on the Monster group is: https://www.youtube.com/watch?v=mH0oCDa74tE <https://www.youtube.com/watch?v=mH0oCDa74tE> As I have explained, the non algorithmic distribution of the codes of the total computable function is enough kicking back for me to be realist on arithmetic, but the Monster group presents, I think, some difficulties for the conventionalist too. Bruno -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/C232267E-B98D-4177-AE23-CCACBBD41BE9%40ulb.ac.be.