Metamath Proof Explorer


Theorem copisnmnd

Description: A structure with a constant group addition operation and at least two elements is not a monoid. (Contributed by AV, 16-Feb-2020)

Ref Expression
Hypotheses copisnmnd.b 𝐵 = ( Base ‘ 𝑀 )
copisnmnd.p ( +g𝑀 ) = ( 𝑥𝐵 , 𝑦𝐵𝐶 )
copisnmnd.c ( 𝜑𝐶𝐵 )
copisnmnd.n ( 𝜑 → 1 < ( ♯ ‘ 𝐵 ) )
Assertion copisnmnd ( 𝜑𝑀 ∉ Mnd )

Proof

Step Hyp Ref Expression
1 copisnmnd.b 𝐵 = ( Base ‘ 𝑀 )
2 copisnmnd.p ( +g𝑀 ) = ( 𝑥𝐵 , 𝑦𝐵𝐶 )
3 copisnmnd.c ( 𝜑𝐶𝐵 )
4 copisnmnd.n ( 𝜑 → 1 < ( ♯ ‘ 𝐵 ) )
5 1 fvexi 𝐵 ∈ V
6 5 a1i ( ( 𝐶𝐵 ∧ 1 < ( ♯ ‘ 𝐵 ) ) → 𝐵 ∈ V )
7 simpr ( ( 𝐶𝐵 ∧ 1 < ( ♯ ‘ 𝐵 ) ) → 1 < ( ♯ ‘ 𝐵 ) )
8 simpl ( ( 𝐶𝐵 ∧ 1 < ( ♯ ‘ 𝐵 ) ) → 𝐶𝐵 )
9 hashgt12el2 ( ( 𝐵 ∈ V ∧ 1 < ( ♯ ‘ 𝐵 ) ∧ 𝐶𝐵 ) → ∃ 𝑐𝐵 𝐶𝑐 )
10 6 7 8 9 syl3anc ( ( 𝐶𝐵 ∧ 1 < ( ♯ ‘ 𝐵 ) ) → ∃ 𝑐𝐵 𝐶𝑐 )
11 df-ne ( 𝐶𝑐 ↔ ¬ 𝐶 = 𝑐 )
12 11 rexbii ( ∃ 𝑐𝐵 𝐶𝑐 ↔ ∃ 𝑐𝐵 ¬ 𝐶 = 𝑐 )
13 rexnal ( ∃ 𝑐𝐵 ¬ 𝐶 = 𝑐 ↔ ¬ ∀ 𝑐𝐵 𝐶 = 𝑐 )
14 12 13 bitri ( ∃ 𝑐𝐵 𝐶𝑐 ↔ ¬ ∀ 𝑐𝐵 𝐶 = 𝑐 )
15 eqidd ( ( ( 𝜑𝑎𝐵 ) ∧ 𝑐𝐵 ) → ( 𝑥𝐵 , 𝑦𝐵𝐶 ) = ( 𝑥𝐵 , 𝑦𝐵𝐶 ) )
16 eqidd ( ( ( ( 𝜑𝑎𝐵 ) ∧ 𝑐𝐵 ) ∧ ( 𝑥 = 𝑎𝑦 = 𝑐 ) ) → 𝐶 = 𝐶 )
17 simpr ( ( 𝜑𝑎𝐵 ) → 𝑎𝐵 )
18 17 adantr ( ( ( 𝜑𝑎𝐵 ) ∧ 𝑐𝐵 ) → 𝑎𝐵 )
19 simpr ( ( ( 𝜑𝑎𝐵 ) ∧ 𝑐𝐵 ) → 𝑐𝐵 )
20 3 adantr ( ( 𝜑𝑎𝐵 ) → 𝐶𝐵 )
21 20 adantr ( ( ( 𝜑𝑎𝐵 ) ∧ 𝑐𝐵 ) → 𝐶𝐵 )
22 15 16 18 19 21 ovmpod ( ( ( 𝜑𝑎𝐵 ) ∧ 𝑐𝐵 ) → ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝐶 )
23 22 adantr ( ( ( ( 𝜑𝑎𝐵 ) ∧ 𝑐𝐵 ) ∧ ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝑐 ) → ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝐶 )
24 simpr ( ( ( ( 𝜑𝑎𝐵 ) ∧ 𝑐𝐵 ) ∧ ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝑐 ) → ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝑐 )
25 23 24 eqtr3d ( ( ( ( 𝜑𝑎𝐵 ) ∧ 𝑐𝐵 ) ∧ ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝑐 ) → 𝐶 = 𝑐 )
26 25 ex ( ( ( 𝜑𝑎𝐵 ) ∧ 𝑐𝐵 ) → ( ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝑐𝐶 = 𝑐 ) )
27 26 ralimdva ( ( 𝜑𝑎𝐵 ) → ( ∀ 𝑐𝐵 ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝑐 → ∀ 𝑐𝐵 𝐶 = 𝑐 ) )
28 27 rexlimdva ( 𝜑 → ( ∃ 𝑎𝐵𝑐𝐵 ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝑐 → ∀ 𝑐𝐵 𝐶 = 𝑐 ) )
29 28 con3d ( 𝜑 → ( ¬ ∀ 𝑐𝐵 𝐶 = 𝑐 → ¬ ∃ 𝑎𝐵𝑐𝐵 ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝑐 ) )
30 rexnal ( ∃ 𝑐𝐵 ¬ ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝑐 ↔ ¬ ∀ 𝑐𝐵 ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝑐 )
31 30 bicomi ( ¬ ∀ 𝑐𝐵 ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝑐 ↔ ∃ 𝑐𝐵 ¬ ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝑐 )
32 31 ralbii ( ∀ 𝑎𝐵 ¬ ∀ 𝑐𝐵 ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝑐 ↔ ∀ 𝑎𝐵𝑐𝐵 ¬ ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝑐 )
33 ralnex ( ∀ 𝑎𝐵 ¬ ∀ 𝑐𝐵 ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝑐 ↔ ¬ ∃ 𝑎𝐵𝑐𝐵 ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝑐 )
34 df-ne ( ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) ≠ 𝑐 ↔ ¬ ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝑐 )
35 34 bicomi ( ¬ ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝑐 ↔ ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) ≠ 𝑐 )
36 35 rexbii ( ∃ 𝑐𝐵 ¬ ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝑐 ↔ ∃ 𝑐𝐵 ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) ≠ 𝑐 )
37 36 ralbii ( ∀ 𝑎𝐵𝑐𝐵 ¬ ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝑐 ↔ ∀ 𝑎𝐵𝑐𝐵 ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) ≠ 𝑐 )
38 32 33 37 3bitr3i ( ¬ ∃ 𝑎𝐵𝑐𝐵 ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) = 𝑐 ↔ ∀ 𝑎𝐵𝑐𝐵 ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) ≠ 𝑐 )
39 29 38 syl6ib ( 𝜑 → ( ¬ ∀ 𝑐𝐵 𝐶 = 𝑐 → ∀ 𝑎𝐵𝑐𝐵 ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) ≠ 𝑐 ) )
40 14 39 syl5bi ( 𝜑 → ( ∃ 𝑐𝐵 𝐶𝑐 → ∀ 𝑎𝐵𝑐𝐵 ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) ≠ 𝑐 ) )
41 10 40 syl5 ( 𝜑 → ( ( 𝐶𝐵 ∧ 1 < ( ♯ ‘ 𝐵 ) ) → ∀ 𝑎𝐵𝑐𝐵 ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) ≠ 𝑐 ) )
42 3 4 41 mp2and ( 𝜑 → ∀ 𝑎𝐵𝑐𝐵 ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) ≠ 𝑐 )
43 2 eqcomi ( 𝑥𝐵 , 𝑦𝐵𝐶 ) = ( +g𝑀 )
44 1 43 isnmnd ( ∀ 𝑎𝐵𝑐𝐵 ( 𝑎 ( 𝑥𝐵 , 𝑦𝐵𝐶 ) 𝑐 ) ≠ 𝑐𝑀 ∉ Mnd )
45 42 44 syl ( 𝜑𝑀 ∉ Mnd )