Functionally complete if you are able to derive functionally complete set <AND,OR,NOT>
F(A,B)=A'+B
F(A,A)=A'+A=1
F(B,B)=B'+B=1
---------------------------------------------------------------
USING 1 as input:-
F(1,B)=1'+B=0+B=B
F(A,1)=A'+1=1
Not able to derive not , hence not functionally complete
--------------------------------------------------------------------------------
http://cs.ucsb.edu/~victor/ta/cs40/posts-criterion.pdf
Theorem. A system of boolean functions is functionally complete if and only if this system does
not entirely belong to any of T0, T1, L, M, S.
The mentioned theorem is called Post's completeness criterion and is due to Emil Post. What this
criterion says is that in order for a system of boolean functions to be functionally complete, this
system should have
• at least one function that does not preserve zero (i.e. it is not in T0), and
• at least one function that does not preserve one (i.e. it is not in T1), and
• at least one function that is not linear (i.e. it is not in L), and
• at least one function that is not monotone (i.e. it is not in M), and
• at least one function that is not self-dual (i.e. it is not in S).
Of course, one function may combine some of these roles, e.g., a function may not preserve one and,
at the same time, not be monotone.
--------------------------------------------------------
using above theorem:-
1. Does not preserve zero as well as one:-
F(0,0)=0'+0=1+0=1
F(1,1)=1'+1=0+1=1 =>> preserve one so not functionally complete