Database
BASIC ALGEBRAIC STRUCTURES
Monoids
Semigroups
df-sgrp
Metamath Proof Explorer
Description: Asemigroup is a set equipped with an everywhere defined internal
operation (so, a magma, see df-mgm ), whose operation is associative.
Definition in section II.1 of Bruck p. 23, or of an "associative
magma" in definition 5 of BourbakiAlg1 p. 4 . (Contributed by FL , 2-Nov-2009) (Revised by AV , 6-Jan-2020)
Ref
Expression
Assertion
df-sgrp
⊢ Smgrp = g ∈ Mgm | [ ˙ Base g / b ] ˙ [ ˙ + g / o ] ˙ ∀ x ∈ b ∀ y ∈ b ∀ z ∈ b x o y o z = x o y o z
Detailed syntax breakdown
Step
Hyp
Ref
Expression
0
csgrp
class Smgrp
1
vg
setvar g
2
cmgm
class Mgm
3
cbs
class Base
4
1
cv
setvar g
5
4 3
cfv
class Base g
6
vb
setvar b
7
cplusg
class + 𝑔
8
4 7
cfv
class + g
9
vo
setvar o
10
vx
setvar x
11
6
cv
setvar b
12
vy
setvar y
13
vz
setvar z
14
10
cv
setvar x
15
9
cv
setvar o
16
12
cv
setvar y
17
14 16 15
co
class x o y
18
13
cv
setvar z
19
17 18 15
co
class x o y o z
20
16 18 15
co
class y o z
21
14 20 15
co
class x o y o z
22
19 21
wceq
wff x o y o z = x o y o z
23
22 13 11
wral
wff ∀ z ∈ b x o y o z = x o y o z
24
23 12 11
wral
wff ∀ y ∈ b ∀ z ∈ b x o y o z = x o y o z
25
24 10 11
wral
wff ∀ x ∈ b ∀ y ∈ b ∀ z ∈ b x o y o z = x o y o z
26
25 9 8
wsbc
wff [ ˙ + g / o ] ˙ ∀ x ∈ b ∀ y ∈ b ∀ z ∈ b x o y o z = x o y o z
27
26 6 5
wsbc
wff [ ˙ Base g / b ] ˙ [ ˙ + g / o ] ˙ ∀ x ∈ b ∀ y ∈ b ∀ z ∈ b x o y o z = x o y o z
28
27 1 2
crab
class g ∈ Mgm | [ ˙ Base g / b ] ˙ [ ˙ + g / o ] ˙ ∀ x ∈ b ∀ y ∈ b ∀ z ∈ b x o y o z = x o y o z
29
0 28
wceq
wff Smgrp = g ∈ Mgm | [ ˙ Base g / b ] ˙ [ ˙ + g / o ] ˙ ∀ x ∈ b ∀ y ∈ b ∀ z ∈ b x o y o z = x o y o z