Metamath Proof Explorer


Theorem odhash

Description: An element of zero order generates an infinite subgroup. (Contributed by Stefan O'Rear, 12-Sep-2015)

Ref Expression
Hypotheses odhash.x X = Base G
odhash.o O = od G
odhash.k K = mrCls SubGrp G
Assertion odhash G Grp A X O A = 0 K A = +∞

Proof

Step Hyp Ref Expression
1 odhash.x X = Base G
2 odhash.o O = od G
3 odhash.k K = mrCls SubGrp G
4 eqid G = G
5 1 4 2 3 odf1o1 G Grp A X O A = 0 x x G A : 1-1 onto K A
6 zex V
7 6 f1oen x x G A : 1-1 onto K A K A
8 hasheni K A = K A
9 5 7 8 3syl G Grp A X O A = 0 = K A
10 ominf ¬ ω Fin
11 znnen
12 nnenom ω
13 11 12 entri ω
14 enfi ω Fin ω Fin
15 13 14 ax-mp Fin ω Fin
16 10 15 mtbir ¬ Fin
17 hashinf V ¬ Fin = +∞
18 6 16 17 mp2an = +∞
19 9 18 eqtr3di G Grp A X O A = 0 K A = +∞