Database of Ring Theory
Toggle navigation
Rings
Browse all rings
Search all rings
Browse commutative rings
Search commutative rings
Browse ring properties
Browse commutative ring properties
Search rings by keyword
Browse rings by dimension
Modules
Browse all modules
Search all modules
Browse module properties
Theorems
Citations
Contribute
Learn
FAQ
Login
Profile
Property: clean
Definition: Every element is the sum of a unit and an idempotent
Reference(s):
N. A. Immormino. Clean rings & clean group rings. (2013) @ .
T. Lam. A crash course on stable range, cancellation, substitution and exchange. (2004) @ .
W. K. Nicholson and Y. Zhou. Clean rings: a survey. (2005) @ .
Metaproperties:
This property has the following metaproperties
passes to matrix rings
stable under finite products
stable under products
passes to quotient rings
forms an equational class
This property
does not
have the following metaproperties
passes to $eRe$ for any idempotent $e$ (Counterexample:
$R_{ 67 }$
)
passes to subrings (Counterexample:
$R_{ 6 }$
is a subring of
$R_{ 101 }$
)
Morita invariant (Counterexample:
$R_{ 83 }$
)
passes to $eRe$ for any full idempotent $e$ (counterexample needed)
passes to polynomial rings (Counterexample:
$R_{ 7 }$
is the polynomial ring of
$R_{ 2 }$
)
Rings
Name
$\mathbb A_\mathbb Q$: the ring of adeles of $\mathbb Q$
$\prod_{i=1}^\infty \mathbb Q[[X,Y]]$
$\widehat{\mathbb Z}$: the profinite completion of the integers
$RCFM_\omega(\mathbb Q)$
Bergman's example showing that "compressible" is not Morita invariant
Bergman's non-unit-regular subring
Bergman's right-not-left primitive ring
Bergman's ring with IBN
Bergman's ring without IBN
Camillo and Nielsen's McCoy ring
Cohn's right-not-left free ideal ring
Cohn's Schreier domain that isn't GCD
Eventually constant sequences in $\mathbb Z$
Faith-Menal counterexample
Grams' atomic domain which doesn't satisfy ACCP
Hurwitz quaternions
Kaplansky's right-not-left hereditary ring
Kasch not semilocal ring
Kerr's Goldie ring with non-Goldie matrix ring
Leavitt path algebra of an infinite bouquet of circles
Left-not-right Noetherian domain
Lipschitz quaternions
Michler & Villamayor's right-not-left V ring
Mori but not Krull domain
Nielsen's semicommutative ring that isn't McCoy
Noetherian domain that is not N-1
Non-Artinian simple ring
O'Meara's infinite matrix algebra
Semicommutative $R$ such that $R[x]$ is not semicommutative
Small's right hereditary, not-left semihereditary ring
$\mathbb Q[\mathbb Q]$
$\mathbb Q[x,x^{-1}]$: Laurent polynomials
$\mathbb Q[x,y,z]/(xz,yz)$
$\mathbb Q[x,y]/(x^2, xy)$
$\mathbb Q[x,y]/(x^2-y^3)$
$\mathbb Q[x]$
$\mathbb Q[x_1, x_2,\ldots, x_n]$
$\mathbb Q\langle a,b\rangle/(a^2)$
$\mathbb Q\langle x, y\rangle$
$\mathbb Q\langle x,y \rangle/(xy-1)$: the Toeplitz-Jacobson algebra
$\mathbb R[x,y]$ completed $I$-adically with $I=(x^2+y^2-1)$
$\mathbb R[x,y]/(x^2+y^2-1)$: ring of trigonometric functions
$\mathbb R[x_1, x_2,x_3,\ldots]$
$\mathbb Z$: the ring of integers
$\mathbb Z+x\mathbb Q[x]$
$\mathbb Z[\frac{1+\sqrt{-19}}{2}]$
$\mathbb Z[\sqrt{-5}]$
$\mathbb Z[i]$: the Gaussian integers
$\mathbb Z[x]$
$\mathbb Z[x]/(x^2-1)$
$\mathbb Z[x_0, x_1,x_2,\ldots]$
$\mathbb Z\langle x,y\rangle/(y^2, yx)$
$\mathbb Z\langle x_0, x_1,x_2,\ldots\rangle$
$\mathbb Z_S$, where $S=((2)\cup(3))^c$
$C([0,1])$, the ring of continuous real-valued functions on the unit interval
$k[x,x^{-1};\sigma]$
Algebra of differential operators on the line (1st Weyl algebra)
Algebraic integers
Base ring for $R_{187}$
Bergman's exchange ring that isn't clean
Bergman's primitive finite uniform dimension ring
Cohn's non-IBN domain
Cozzens simple, left principal, right non-Noetherian domain
Cozzens' simple V-domain
Facchini's torch ring
Finitely cogenerated, not semilocal ring
Hochster's connected, nondomain, locally-domain ring
Kolchin's simple V-domain
Malcev's nonembeddable domain
McGovern's commutative Zorn ring that isn't clean
Nagata's Noetherian infinite Krull dimension ring
Nielsen's right UGP, not left UGP ring
Non lift/rad matrix ring over a lift/rad base ring
non-$h$-local domain
Non-symmetric $2$-primal ring
Nonlocal endomorphism ring of a uniserial module
Osofsky's Type I ring
Progression free polynomial ring
Ram's Ore extension ring
reduced $I_0$ ring that is not exchange
Right-not-left ACC on annihilators triangular ring
Right-not-left Noetherian triangular ring
Right-not-left nonsingular ring
Ring of holomorphic functions on $\mathbb C$
Shepherdson's domain that is not stably finite
Simple, Noetherian ring with zero divisors and trivial idempotents
Square of a torch ring
Trivial extension torch ring
Šter's counterexample showing "clean" is not Morita invariant
$2$-adic integers: $\mathbb Z_2$
$\mathbb C$: the field of complex numbers
$\mathbb H$: Hamilton's quaternions
$\mathbb Q$: the field of rational numbers
$\mathbb Q(x)$: rational functions over the rational numbers
$\mathbb Q+FM_\omega(\mathbb Q)$
$\mathbb Q[[X]]$
$\mathbb Q[[x^2,x^3]]$
$\mathbb Q[X,Y]_{(X,Y)}$
$\mathbb Q[x,y]_{(x,y)}/(x^2-y^3)$
$\mathbb Q[x^{1/2},x^{1/4},x^{1/8},...]/(x)$
$\mathbb R$: the field of real numbers
$\mathbb R[[x]]$
$\mathbb R[x,y,z]/(x^2,y^2, xz,yz,z^2-xy)$
$\mathbb R[x]/(x^2)$
$\mathbb Z/(2)$
$\mathbb Z/(n)$, $n$ divisible by two primes and a square
$\mathbb Z/(n)$, $n$ squarefree and not prime
$\mathbb Z/(p)$, $p$ an odd prime
$\mathbb Z/(p^k)$, $p$ a prime, $k>1$
$\mathbb Z[X]/(X^2,4X, 8)$
$\mathbb Z[X]/(X^2,8)$
$\mathbb Z_{(2)}$
$\prod_{i=0}^\infty \mathbb Q$
$\prod_{i=1}^\infty \mathbb Z/(2^i)$
$\prod_{i=1}^\infty F_2$
$\varinjlim T_{2^n}(\Bbb Q)$
$\varinjlim \mathbb Q^{2^n}$
$\varinjlim M_{2^n}(\mathbb Q)$
$^\ast \mathbb R$: the field of hyperreal numbers
$C\ell_{2,1}(\mathbb R)$: the geometric algebra of Minkowski 3-space
$C^\infty_0(\mathbb R)$: the ring of germs of smooth functions on $\mathbb R$ at $0$
$F_2[\mathcal Q_8]$
$F_2[S_4]$
$F_2[x,y]/(x,y)^2$
$F_p(x)$
$k[[x,y]]/(x^2,xy)$
$k[x;\sigma]/(x^2)$ (Artinian)
$k[x;\sigma]/(x^2)$ (not right Artinian)
$M_n(\mathbb Q)$
$M_n(F_2)$
$T_\omega(\mathbb Q)$
$T_n(\mathbb Q)$: the upper triangular matrix ring over $\mathbb Q$
$T_n(F_2)$
$T_n(F_q)$
10-adic numbers
2-dimensional uniserial domain
2-truncated Witt vectors over $\Bbb F_2((t))$
Akizuki's counterexample
Algebraic closure of $F_2$
Basic ring of Nakayama's QF ring
Bass's right-not-left perfect ring
Berberian's incompressible Baer ring
Bergman's unit-regular ring
catenary, not universally catenary
Chase's left-not-right semihereditary ring
Clark's uniserial ring
Countably infinite boolean ring
Custom Krull dimension valuation ring
Division algebra with no anti-automorphism
Division ring with an antihomomorphism but no involution
DVR that is not N-2
field of $2$-adic numbers
Field of algebraic numbers
Field of constructible numbers
Full linear ring of a countable dimensional right vector space
Goodearl's simple self-injective operator algebra
Goodearl's simple self-injective von Neumann regular ring
Grassmann algebra $\bigwedge (V)$, $\dim(V)=\aleph_0$
Henselization of $\Bbb Z_{(2)}$
Interval monoid ring
Left-not-right pseudo-Frobenius ring
Left-not-right uniserial domain
Local right-not-left Kasch ring
McCoy ring that is not Abelian
Nagata ring that not quasi-excellent
Nagata's normal ring that is not analytically normal
Nakayama's quasi-Frobenius ring that isn't Frobenius
Noetherian ring that is not Grothendieck and not Nagata
Osofsky's $32$ element ring
Page's left-not-right FPF ring
Perfect non-Artinian ring
Perfect ring that isn't semiprimary
Pseudo-Frobenius, not quasi-Frobenius ring
Puninski's triangular serial ring
Quasi-continuous ring that is not Ikeda-Nakayama
Rational quaternions
reduced exchange ring which is not semiregular
Reversible non-symmetric ring
Right-not-left Artinian triangular ring
Right-not-left coherent ring
Right-not-left Kasch ring
Right-not-left simple injective ring
ring of germs of holomorphic functions on $\mathbb C^n$, $n>1$
Samuel's UFD having a non-UFD power series ring
Simple, non-Artinian, von Neumann regular ring
Varadarajan's left-not-right coHopfian ring
Šter's clean ring with non-clean corner rings
Legend
= has the property
= does not have the property
= information not in database