Abbreviation: SRng0
A \emph{semiring with zero} is a structure S=⟨S,+,0,⋅⟩ of type ⟨2,0,2⟩ such that
⟨S,+,0⟩ is a commutative monoid
⟨S,⋅⟩ is a semigroup
0 is a zero for ⋅: 0⋅x=0, x⋅0=0
⋅ distributes over +: x⋅(y+z)=x⋅y+x⋅z, (y+z)⋅x=y⋅x+z⋅x
Let S and T be semirings with zero. A morphism from S to T is a function h:S→T that is a homomorphism:
h(x+y)=h(x)+h(y), h(x⋅y)=h(x)⋅h(y), h(0)=0
Example 1:
f(1)=1f(2)=4f(3)=22f(4)=283f(5)=f(6)=