What does it mean for a language not to be complete?

[S.ALGH]

Anyone can explain to me What does it mean for a language not to be complete?

for example P has 2 languages are not complete for P

ø and {0,1} are not complete for P.

 

[jedishrfu]

Welcome to PF!

Are you referring to Turing completeness?

https://en.wikipedia.org/wiki/Turing_completeness

 

[S.ALGH]

Then why ø and {0,1} are not complete for P (polynomial) ??

 

[jedishrfu]

What is the context of your question? What subject are you studying? Math or computer science?

 

[S.ALGH]

it is computer science, and the question is : A language L is complete for a language class C with respect to polynomial time reduction if L belongs to C and L' <=p L for all L' belong to C. Show that ø and {0,1} are the only languages in P that are not complete for P with respect to polynomial time reductions.

I started solving the question by proving that L belongs to P, but I did not understand how to show that ø and {0,1} are the only languages in P that are not complete ??