[Home]Near-fields

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Near-rings

Near-rings with identity


Abbreviation: NFld

Definition

A near-field is a near-ring with identity N = (N, + ,−,0,·,1 ) such that
N is non-trivial:   0 ≠ 1 and
every non-zero element has a multiplicative inverse:   x ≠ 0  ⇒  ∃y (x·y = 1).

Remark: The inverse of x is unique, and is usually denoted by x−1.

Morphisms

Let M and N be near-fields. A morphism from M to N is a function h : MN that is a homomorphism: h(x + y) = h(x) + h(y)  and  h(x·y) = h(xh(y).

Remark: It follows that h(0) = 0 and h(−x) = −h(x).

Some results

0 is a zero for ·: x = 0 and x·0 = 0.

Examples

Properties

Classtype first-order
Equational theory
Quasiequational theory
First-order theory
Locally finite no
Residual size unbounded
Congruence distributive
Congruence modular yes
Congruence n-permutable yes, n = 2
Congruence regular yes
Congruence uniform yes
Congruence extension property
Definable principal congruences
Equationally definable principal congruences
Amalgamation property
Strong amalgamation property
Epimorphisms are surjective

Finite members

[Size 1]?:  1
[Size 2]?:  
[Size 3]?:  
[Size 4]?:  
[Size 5]?:  
[Size 6]?:  

Subclasses

Fields

Superclasses

Near-rings with identity


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Last edited April 19, 2003 9:43 pm (diff)
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