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
vote
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
votes
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
votes
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
vote
0answers
101 views
Substitution semiring?
Let G be a [ CF ] grammar, and let elements of semiring be sets of rules.
Define multiplication as:
$$ x\otimes y = \{ t| \exists r \in x \exists s \in y (t=subst(r,s))\} $$
…

