Table of Contents
Algebras
Some 1-element algebras
Some 2-element algebras
Some 3-element algebras
Some 4-element algebras
Some 5-element algebras
Some 6-element algebras
Some n-element algebras
Some infinite algebras
Algebras
Some 1-element algebras
1-element boolean algebra
$\mathbb B_1=\langle\{0\},\vee,0,\wedge,0,'\rangle$
1-element chain
$\mathbb C_1=\langle\{0\},\vee,\wedge\rangle$
1-element group
$\mathbb Z_1=\langle\{0\},+_1,-_1,0\rangle$
1-element mono-unary algebra
$\mathbb U_1=\langle\{0\},0\rangle$
1-element semilattice
$\mathbb S_1=\langle\{0\},\cdot\rangle$
1-element set
$\mathbf 1=\langle\{0\}\rangle$
Some 2-element algebras
2-element boolean algebra
$\mathbb B_2=\langle\{0,1\},\vee,0,\wedge,1,'\rangle$
2-element chain
$\mathbb C_2=\langle\{0,1\},\vee,\wedge\rangle$
2-element cyclic group
$\mathbb Z_2=\langle\{0,1\},+_2,-_2,0\rangle$
2-element field
$\mathbb F_2=\langle\{0,1\},+_2,-_2,0,\cdot_2,1\rangle$
2-element mono-unary algebras
$\mathbb U_{2,0}=\langle\{0,1\},0\rangle$, $\mathbb U_{2,1}=\langle\{0,1\},1\rangle$, $\mathbb U_{2,'}=\langle\{0,1\},'\rangle$
2-element semilattice
$\mathbb S_2=\langle\{0,1\},\cdot\rangle$
2-element set
$\mathbf 2=\langle\{0,1\}\rangle$
Some 3-element algebras
3-element chain
$\mathbb C_3=\langle\{0,1,2\},\vee,\wedge\rangle$
3-element cyclic group
$\mathbb Z_3=\langle\{0,1,2\},+_3,-_3,0\rangle$
3-element field
$\mathbb F_3=\langle\{0,1,2\},+_3,-_3,0,\cdot_3,1\rangle$
3-element semilattices
$\mathbb S_{3,0}=\langle\{0,1,2\},\cdot\rangle$, $\mathbb S_{3,1}=\langle\{0,1,2\},\min\rangle$
Some 4-element algebras
4-element boolean algebra
$\mathbb B_2^2=\langle\{0,1,2,3\},\vee,0,\wedge,3,'\rangle$
4-element chain
$\mathbb C_4=\langle\{0,1,2,3\},\vee,\wedge\rangle$
4-element cyclic group
$\mathbb Z_4=\langle\{0,1,2,3\},+_4,-_4,0\rangle$
4-element distributive lattice
$(\mathbb C_2)^2=\langle\{(0,0),(0,1),(1,0),(1,1)\},\vee,\wedge\rangle$
4-element field
$\mathbb F_4=\langle\{0,1,x,x+1\},+_2,-_2,0,\cdot,1\rangle\cong\mathbb F_2[x]/\langle x^2+x+1\rangle$
4-element noncyclic group
$(\mathbb Z_2)^2=\langle\{(0,0),(0,1),(1,0),(1,1)\},+_2,-_2,(0,0)\rangle$
4-element nonunital rings
$\mathbb Z_{4,0}=\langle\{0,1,2,3\},+_4,-_4,0,\cdot_0\rangle$, $(\mathbb F_2)^2=\langle\{(0,0),(0,1),(1,0),(1,1)\},+_2,-_2,(0,0),\cdot_0\rangle$
4-element unital rings
$\mathbb Z_{4,1}=\langle\{0,1,2,3\},+_4,-_4,0,\cdot_4,1\rangle$, $(\mathbb F_2)^2=\langle\{(0,0),(0,1),(1,0),(1,1)\},+_2,-_2,(0,0),\cdot,(1,1)\rangle$
Some 5-element algebras
5-element chain
$\mathbb C_5=\langle\{0,1,2,3,4\},\vee,\wedge\rangle$
5-element cyclic group
$\mathbb Z_5=\langle\{0,1,2,3,4\},+_5,-_5,0\rangle$
Some 6-element algebras
6-element nonabelian group
$S_3=\langle\{(),(12),(13),(23),(123),(132)\},\circ,{}^{-1},()\rangle$
Some n-element algebras
2^k-element boolean algebra
$\mathbb B_2^k=\langle\{0,1,2,\ldots,2^k-1\},\vee,0,\wedge,2^k-1,'\rangle$
k!-element symmetric group
$S_k=\langle\{$permutations on $k$-element set$\},\circ,{}^{-1},()\rangle$
n-element chain
$\mathbb C_n=\langle\{0,1,2,\ldots,n-1\},\vee,\wedge\rangle$
n-element cyclic group
$\mathbb Z_n=\langle\{0,1,2,\ldots,n-1\},+_n,-_n,0\rangle$
p^k-element field
$\mathbb F_{p^k}=\langle\{0,1,\ldots,p-1,x,\ldots\},+_p,-_p,0,\cdot,1\rangle\cong\mathbb F_p[x]/\langle f(x)\rangle$
Some infinite algebras
Positive integers additive semigroup
$\langle \mathbb Z^+,+\rangle$
Positive integers monoid
$\langle \mathbb Z^+,\cdot,1\rangle$
Natural numbers additive monoid
$\langle \mathbb N,+,0\rangle$
Natural numbers multiplicative monoid
$\langle \mathbb N,\cdot,1\rangle$
Integers additive group
$\langle \mathbb Z,+,-,0\rangle$
Integers ring
$\langle \mathbb Z,+,-,0,\cdot,1\rangle$
Integers lattice-ordered group
$\langle \mathbb Z,\vee,\wedge,+,-,0\rangle$
Rational numbers additive group
$\langle \mathbb Q,+,-,0\rangle$
Positive rational numbers group
$\langle \mathbb Q^+,\cdot,{}^{-1},1\rangle$
Rational numbers field
$\langle \mathbb Q,+,-,0,\cdot,1\rangle$
Real numbers field
$\langle \mathbb R,+,-,0,\cdot,1\rangle$
Gaussian integers ring
$\langle \mathbb Z[i],+,-,0,\cdot,1\rangle$
Complex numbers field
$\langle \mathbb C,+,-,0,\cdot,1\rangle$
Natural number chain
$\langle \mathbb N,\vee,\wedge\rangle$
Negative integer chain
$\langle \mathbb Z^-,\vee,\wedge\rangle$
Integer chain
$\langle \mathbb Z,\vee,\wedge\rangle$
Rational number chain
$\langle \mathbb Q,\vee,\wedge\rangle$