Definition

An ordered blue field is a nontrivial FF such that

F=F×{0};F^\bullet=F^\times\sqcup\{0\};

that is, every nonzero element of its underlying multiplicative monoid is invertible.

Scope

The term concerns the monomial skeleton FF^\bullet. It does not assert that the ambient semiring F+F^+ is a field, nor does it by itself supply additive inverses or unique weak inverses.

Fields, , and hyperfields have ordered-blue-field avatars after their additive data are encoded in the order. General ordered blue fields form a larger class. Additional conditions define and .

References

Matthew Baker and Oliver Lorscheid, The moduli space of matroids, §§2.6 and 6.4.