If P1<=P2 means P1 is reducible to p2,then which is true?
1, If P1 is RE But Not REC,P2 is also RE but not REC?
2. If P2 is RE But Not REC,P1 is also RE but not REC?
As per my understanding ,if P1 is undecidable then P2 is undecidable,so If i consider RE BUT NOT REC as undecidable,then answer will be 1 is true
Also i know if P2 is RE then P1 is also RE is correct,As per this result,RE BUT NOT REC is also RE,so 2 is true.
Please help
Edit:- As a part of this solution please tell me,whether undecidable includes semidecidable also?And whether semidecidable includes decidable also?