30.9 Mappings that Respect Addition

  • RespectsAddition( mapp ) P

    Let mapp be a general mapping with underlying relation F Í S ×R, where S and R are the source and the range of mapp, respectively. Then RespectsAddition returns true if S and R are additive magmas such that (s1,r1), (s2,r2) Î F implies (s1 + s2,r1 + r2) Î F, and false otherwise.

    If mapp is single-valued then RespectsAddition returns true if and only if the equation s1^mapp + s2^mapp = (s1+s2)^mapp holds for all s1, s2 in S.

  • RespectsAdditiveInverses( mapp ) P

    Let mapp be a general mapping with underlying relation F Í S ×R, where S and R are the source and the range of mapp, respectively. Then RespectsAdditiveInverses returns true if S and R are additive-magmas-with-inverses such that (s,r) Î F implies (-s,-r) Î F, and false otherwise.

    If mapp is single-valued then RespectsAdditiveInverses returns true if and only if the equation AdditiveInverse( s )^mapp = AdditiveInverse( s^mapp ) holds for all s in S.

  • RespectsZero( mapp ) P

    Let mapp be a general mapping with underlying relation F Í S ×R, where S and R are the source and the range of mapp, respectively. Then RespectsZero returns true if S and R are additive-magmas-with-zero such that ( Zero(¢S¢), Zero(¢R¢) ) Î F, and false otherwise.

    If mapp is single-valued then RespectsZero returns true if and only if the equation Zero( S )^mapp = Zero( R ) holds.

  • IsAdditiveGroupGeneralMapping( mapp ) P
  • IsAdditiveGroupHomomorphism( mapp ) P

  • KernelOfAdditiveGeneralMapping( mapp ) A

    Let mapp be a general mapping. Then KernelOfAdditiveGeneralMapping returns the set of all elements in the source of mapp that have the zero of the range in their set of images.

  • CoKernelOfAdditiveGeneralMapping( mapp ) A

    Let mapp be a general mapping. Then CoKernelOfAdditiveGeneralMapping returns the set of all elements in the rqange of mapp that have the zero of the source in their set of preimages.

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    GAP 4 manual
    February 2000