subring
Noun
Meaning
subring (plural subrings)
(algebra) a ring which is contained in a larger ring, such that the multiplication and addition on the former are a restriction of those on the latter.
Phrases with the word
Anagrams
Examples
It turns out that, although ker f is generally not a subring of R since it may not contain the multiplicative identity if S is not the null ring (although the kernel is a subring for nonunital rings).
The first isomorphism theorem for rings states that this quotient ring is naturally isomorphic to the image of f (which is a subring of S).
Examples The most basic example is a ring itself; it is an algebra over its center or any subring lying in the center.
On the other hand, the subset of even integers 2Z does not contain the identity element 1 and thus does not qualify as a subring.
Since the Burnside ring is contained as a finite index subring of the representation ring, one can pass easily from one to the other by extending the coefficients from integers to the rational numbers.
The ring of continuous functions in the previous example is a subring of this ring if X is the real line and R is the field of real numbers.