let I be non empty set ; for F being Group-like associative multMagma-Family of I
for i being Element of I
for g being Element of (product F) st g in ProjSet (F,i) holds
g " in ProjSet (F,i)
let F be Group-like associative multMagma-Family of I; for i being Element of I
for g being Element of (product F) st g in ProjSet (F,i) holds
g " in ProjSet (F,i)
let i be Element of I; for g being Element of (product F) st g in ProjSet (F,i) holds
g " in ProjSet (F,i)
let g be Element of (product F); ( g in ProjSet (F,i) implies g " in ProjSet (F,i) )
assume A1:
g in ProjSet (F,i)
; g " in ProjSet (F,i)
consider z being Element of (F . i) such that
A2:
g = (1_ (product F)) +* (i,z)
by Def1, A1;
g " = (1_ (product F)) +* (i,(z "))
by Th4, A2;
hence
g " in ProjSet (F,i)
by Def1; verum