Equivalence of definitions of image-closed characteristic subgroup of finite abelian group

From Groupprops

Statement

Suppose in a finite abelian group and is a subgroup of . The following are equivalent:

  1. is an Image-closed characteristic subgroup (?) of : for any surjective homomorphism from , the image of is characteristic in the image of .
  2. is an Image-closed fully invariant subgroup (?) of : for any surjective homomorphism from , the image of is fully invariant in the image of .
  3. is a Verbal subgroup (?) of .
  4. For every prime , the -Sylow subgroup of is an agemo subgroup of the -Sylow subgroup of .

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