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Abelian Groups - László Fuchs [Springer]

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xviii<br />

Table of Notations<br />

MA: Martin’s Axiom<br />

Ab: category of abelian groups<br />

C; D;:::: categories<br />

V; V p : category of valuated groups or vector spaces<br />

G; H;:::: G./; H./-families of subgroups<br />

Maps<br />

!: mapping, homomorphism<br />

A ˛!B: map˛ from A to B<br />

7!: corresponds to<br />

P!: quasi-homomorphism<br />

1 A : identity map on A<br />

Pn: multiplication by integer n<br />

A: restriction of map to A<br />

Im : image of map <br />

Ker :kernelofmap<br />

Coker : cokernel of map <br />

; r: diagonal, codiagonal map<br />

˚ i : direct sum of maps i<br />

Q<br />

i : direct product of maps i<br />

[ i i : union of a chain of maps<br />

e W 0 ! A ! B ! C ! 0: exact sequence<br />

<strong>Groups</strong>, rings<br />

0: number 0, element 0, or subgroup f0g<br />

N: set of positive integers<br />

Z: group of integers<br />

Q: group of rational numbers<br />

R: group of real numbers<br />

C: group of complex numbers<br />

T Š R=Z: group of complex numbers of absolute value 1<br />

Z.n/: cyclic group of order n<br />

Z.p 1 /: quasi-cyclic p-group<br />

Z .p/ : group or ring of rational numbers with denominators coprime to p<br />

Q .p/ : group or ring of rational numbers whose denominators are powers of p<br />

J p : group or ring of p-adic integers<br />

Q p : group or field of p-adic numbers<br />

H : generalized Prüfer group of length

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