OpenMath Content Dictionary: semigroup2

Canonical URL:
http://www.openmath.org/cd/semigroup2.ocd
CD Base:
http://www.openmath.org/cd
CD File:
semigroup2.ocd
CD as XML Encoded OpenMath:
semigroup2.omcd
Defines:
is_automorphism, is_endomorphism, is_homomorphism, is_isomorphism, isomorphic, left_multiplication, right_multiplication
Date:
2004-06-01
Version:
1 (Revision 1)
Review Date:
2006-06-01
Status:
experimental

Basic functions for semigroup theory

Initiated by Arjeh M. Cohen 2003-10-03

is_homomorphism

Description:

This symbol is a boolean function with three arguments. The first and arguments are semigroups M, N, the third is a map f from the element set of M to the element set of N. When applied to M, N, and f, it denotes that f is a semigroup homomorphism from M to N.

Commented Mathematical property (CMP):
If is_homomorphism(M,N,f) then, for each pair of elements x, y of M, we have f(x * y) = f(x) * f(y).
Formal Mathematical property (FMP):
is_homomorphism ( M , N , f ) x , y . x carrier ( M ) y carrier ( G ) f ( x y ) = f ( y ) f ( x )
Example:
is_homomorphism ( M , N , f )
Signatures:
sts


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is_isomorphism

Description:

This symbol is a boolean function with three arguments. The first and arguments are semigroups M, N, the third is a map f from the element set of M to the element set of N. When applied to M, N, and f, it denotes that f is a semigroup isomorphism from M to N. This means that f is a homomorphism from M to N, that f is bijective, and that its inverse is a homomorphism from N to M.

Example:
is_isomorphism ( M , N , f )
Signatures:
sts


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is_endomorphism

Description:

This symbol is a boolean function with two arguments. The first argument is a semigroup M, the second is a map f from the element set of M to the element set of M. When applied to M and f, it denotes that f is a semigroup endomorphism from M to M.

Commented Mathematical property (CMP):
If is_endomorphism(M,f) then is_homomorphism(M,M,f)
Formal Mathematical property (FMP):
is_endomorphism ( M , f ) is_homomorphism ( M , M , f )
Example:
is_endomorphism ( M , f )
Signatures:
sts


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is_automorphism

Description:

This symbol is a boolean function with two arguments. The first is a semigroup M, the second is a map f from the element set of M to the element set of M. When applied to M and f, it denotes a semigroup automorphism f of M.

Commented Mathematical property (CMP):
If is_automorphism(M,f) then is_isomorphism(M,M,f)
Formal Mathematical property (FMP):
is_automorphism ( M , f ) is_isomorphism ( M , M , f )
Example:
is_automorphism ( M , f )
Signatures:
sts


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left_multiplication

Description:

This symbol is a function with two arguments, which should be a semigroup M and an element x of M. When applied to M and x, it denotes left multiplication on M by x.

Commented Mathematical property (CMP):
left_multiplication(M,x) (y) = x * y.
Formal Mathematical property (FMP):
M , x , y . ( left_multiplication ( M , x ) ) ( y ) = multiplication ( M , x , y )
Signatures:
sts


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right_multiplication

Description:

This symbol is a function with two arguments, which should be a semigroup M and an element x of M. When applied to M and x, it denotes right multiplication on M by x.

Commented Mathematical property (CMP):
right_multiplication(M,x) (y) = y * x.
Formal Mathematical property (FMP):
M , x , y . ( right_multiplication ( M , x ) ) ( y ) = multiplication ( M , y , x )
Signatures:
sts


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isomorphic

Description:

This symbol is a Boolean function with n arguments, n at least 2, which are semigroups. When applied to M_1, ..., M_n, it denotes the fact that there is an isomorphism from each M_i to each M_j.

Example:
isomorphic ( M , N )
Signatures:
sts


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