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Theorem 0mgm 47414
Description: A set with an empty base set is always a magma. (Contributed by AV, 25-Feb-2020.)
Hypothesis
Ref Expression
0mgm.b (Base‘𝑀) = ∅
Assertion
Ref Expression
0mgm (𝑀𝑉𝑀 ∈ Mgm)

Proof of Theorem 0mgm
Dummy variables 𝑥 𝑦 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 ral0 4514 . 2 𝑥 ∈ ∅ ∀𝑦 ∈ ∅ (𝑥(+g𝑀)𝑦) ∈ ∅
2 0mgm.b . . . 4 (Base‘𝑀) = ∅
32eqcomi 2734 . . 3 ∅ = (Base‘𝑀)
4 eqid 2725 . . 3 (+g𝑀) = (+g𝑀)
53, 4ismgm 18604 . 2 (𝑀𝑉 → (𝑀 ∈ Mgm ↔ ∀𝑥 ∈ ∅ ∀𝑦 ∈ ∅ (𝑥(+g𝑀)𝑦) ∈ ∅))
61, 5mpbiri 257 1 (𝑀𝑉𝑀 ∈ Mgm)
Colors of variables: wff setvar class
Syntax hints:  wi 4   = wceq 1533  wcel 2098  wral 3050  c0 4322  cfv 6549  (class class class)co 7419  Basecbs 17183  +gcplusg 17236  Mgmcmgm 18601
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1789  ax-4 1803  ax-5 1905  ax-6 1963  ax-7 2003  ax-8 2100  ax-9 2108  ax-ext 2696  ax-nul 5307
This theorem depends on definitions:  df-bi 206  df-an 395  df-or 846  df-3an 1086  df-tru 1536  df-fal 1546  df-ex 1774  df-sb 2060  df-clab 2703  df-cleq 2717  df-clel 2802  df-ne 2930  df-ral 3051  df-rab 3419  df-v 3463  df-sbc 3774  df-dif 3947  df-un 3949  df-ss 3961  df-nul 4323  df-if 4531  df-sn 4631  df-pr 4633  df-op 4637  df-uni 4910  df-br 5150  df-iota 6501  df-fv 6557  df-ov 7422  df-mgm 18603
This theorem is referenced by: (None)
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