Tagged Questions

1
vote
2answers
183 views

Semiring naturally associated to any monoid?

For any monoid $M$, we can naturally construct a semiring $S$ as follows: Let the additive monoid of $S$ be the free commutative monoid on $M$ Let the multiplicative monoid of $S …
2
votes
0answers
81 views

Semirings where solving linear systems is in P

Solving linear systems appears hard in semirings. In $\mathbb{N}_0 (+,\times)$ it is NP-complete via reduction to 1-in-3 SAT. In the min-plus semiring the complexity is $ NP \cap …
0
votes
2answers
214 views

commutative rigs and the Grothendieck Group

If I start with a commutative rig, and apply the Grothendieck Group construction to it, twice, once to the additive structure and once to the multiplicative structure, is the resul …
2
votes
1answer
196 views

Semirings with subtractive primes

Let $S$ be a commutative semiring with identity such that each prime ideal of $S$ is subtractive. Does this imply all ideals of $S$ to be subtractive? By a commutative semiring wi …
1
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0answers
61 views

q-product semiring

q-product is defined as $x \otimes _q y = (x^{1-q}+y^{1-q}-1)^{1/(1-q)}$ Observation: $(+,\otimes_\infty)$ is min-plus tropical semiring on the segment $[0,1]$ $(+,\otimes_1)$ …
2
votes
1answer
160 views

Dual of idempotent semirings

By an idempotent semiring I mean a set equipped with a join-semilattice with bottom structure $(0,+)$ and a multiplicative monoid $(1,\cdot)$ such that the following equations hold …
0
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0answers
62 views

Lower bounding the number of summands in a sum representation of a nonnegative function

Hi everybody, let $f: [n] \times [n] \rightarrow \mathbb R_+$ be a nonnegative function and suppose that $f = \sum_{i = 1}^m f_i$ where the $f_i: [n] \times [n] \rightarrow \mathb …
17
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0answers
691 views

Mikhalkin’s tropical schemes versus Durov’s tropical schemes

In Mikhalkin's unfinished draft book on tropical geometry, (available here) (page 26) he defines a notion of tropical schemes. It seems to me that this definition is not just a who …
1
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0answers
101 views

Substitution semiring?

Let G be a [ CF ] grammar, and let elements of semiring be sets of rules. Define multiplication as: $$ x\otimes y = \{ t| \exists r \in x \exists s \in y (t=subst(r,s))\} $$ …