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Theorem mndsgrp 17122
Description: A monoid is a semigroup. (Contributed by FL, 2-Nov-2009.) (Revised by AV, 6-Jan-2020.) (Proof shortened by AV, 6-Feb-2020.)
Assertion
Ref Expression
mndsgrp (𝐺 ∈ Mnd → 𝐺 ∈ SGrp)

Proof of Theorem mndsgrp
Dummy variables 𝑒 𝑥 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 eqid 2610 . . 3 (Base‘𝐺) = (Base‘𝐺)
2 eqid 2610 . . 3 (+g𝐺) = (+g𝐺)
31, 2ismnddef 17119 . 2 (𝐺 ∈ Mnd ↔ (𝐺 ∈ SGrp ∧ ∃𝑒 ∈ (Base‘𝐺)∀𝑥 ∈ (Base‘𝐺)((𝑒(+g𝐺)𝑥) = 𝑥 ∧ (𝑥(+g𝐺)𝑒) = 𝑥)))
43simplbi 475 1 (𝐺 ∈ Mnd → 𝐺 ∈ SGrp)
Colors of variables: wff setvar class
Syntax hints:  wi 4  wa 383   = wceq 1475  wcel 1977  wral 2896  wrex 2897  cfv 5804  (class class class)co 6549  Basecbs 15695  +gcplusg 15768  SGrpcsgrp 17106  Mndcmnd 17117
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1713  ax-4 1728  ax-5 1827  ax-6 1875  ax-7 1922  ax-10 2006  ax-11 2021  ax-12 2034  ax-13 2234  ax-ext 2590  ax-nul 4717
This theorem depends on definitions:  df-bi 196  df-or 384  df-an 385  df-3an 1033  df-tru 1478  df-ex 1696  df-nf 1701  df-sb 1868  df-eu 2462  df-clab 2597  df-cleq 2603  df-clel 2606  df-nfc 2740  df-ral 2901  df-rex 2902  df-rab 2905  df-v 3175  df-sbc 3403  df-dif 3543  df-un 3545  df-in 3547  df-ss 3554  df-nul 3875  df-if 4037  df-sn 4126  df-pr 4128  df-op 4132  df-uni 4373  df-br 4584  df-iota 5768  df-fv 5812  df-ov 6552  df-mnd 17118
This theorem is referenced by:  mndmgm  17123  mndass  17125  mndsssgrp  17244  grpsgrp  17269  mulgnn0dir  17394  mulgnn0ass  17401  ringrng  41669
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