Metamath Proof Explorer


Theorem degenmgmbas

Description: The base set of a degenerate magma. (Contributed by AV, 21-Aug-2026)

Ref Expression
Hypotheses degenmgm.m
|- M = { <. ( Base ` ndx ) , { (/) , 1o } >. , <. ( +g ` ndx ) , { <. <. 1o , 1o >. , 1o >. , <. <. 1o , 2o >. , 1o >. , <. <. 1o , (/) >. , 1o >. } >. }
degenmgmbas.b
|- B = ( Base ` M )
Assertion degenmgmbas
|- B = { (/) , 1o }

Proof

Step Hyp Ref Expression
1 degenmgm.m
 |-  M = { <. ( Base ` ndx ) , { (/) , 1o } >. , <. ( +g ` ndx ) , { <. <. 1o , 1o >. , 1o >. , <. <. 1o , 2o >. , 1o >. , <. <. 1o , (/) >. , 1o >. } >. }
2 degenmgmbas.b
 |-  B = ( Base ` M )
3 prex
 |-  { (/) , 1o } e. _V
4 1 grpbase
 |-  ( { (/) , 1o } e. _V -> { (/) , 1o } = ( Base ` M ) )
5 3 4 ax-mp
 |-  { (/) , 1o } = ( Base ` M )
6 2 5 eqtr4i
 |-  B = { (/) , 1o }