A ring endomorphism of a ring 
is a ring homomorphism
from 
to itself. Ring endomorphisms include the identity map and are closed under function
composition.
Ring Endomorphism
See also
Endomorphism Ring, Ring Automorphism, Ring Homomorphism, Ring MonomorphismExplore with Wolfram|Alpha
References
Dummit, D. S. and Foote, R. M. "Ring Homomorphisms and Quotient Rings." §7.3 in Abstract Algebra, 3rd ed. Hoboken, NJ: Wiley, pp. 239-250, 2004.Cite this as:
Weisstein, Eric W. "Ring Endomorphism." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/RingEndomorphism.html