How can I prove Sb5 and Sb6 with the given axioms (Com, As, Dis, Id, Cmp) and the previous Sb's?
For Sb5 I understand I need to use Id, but I don't know where to start. Same with Sb6.
>>114750
A∩Ac = Ac∩A = 0 (com, cmp)
A∪Ac = Ac∪A = U (com, cmp)
A'=Ac, B'=A then A=B'=A'c=Acc (sb5)
>>114789
Thanks!
Bumping this.
I'm still trying to work out Sb5 and I'm getting nowhere.
>>115275
Finally came up with this.
Can anyone check if it's solid? Sub = substitution, H1 = hypothesis 1, H2 = hypothesis 2
>>115379
Seems okay, but you can shorten some steps.
Start with (Id) B ∩ U = B
Also in 7-> 8 you need an extra step.