Without using Truth table find the PCNF and PDNF of (P->(Q^R)) ^ (7P->(7Q ^ 7R)).

To find the Principal Conjunctive Normal Form (PCNF) and Principal Disjunctive Normal Form (PDNF) of the expression \((P \rightarrow (Q \land R)) \land (\neg P \rightarrow (\neg Q \land \neg R))\), we can follow a systematic approach.

### Step 1: Express the implications in terms of disjunctions
Recall that \( P \rightarrow A \) is equivalent to \( \neg P \lor A \).

1. **First Implication**:  
   \[
   P \rightarrow (Q \land R) \equiv \neg P \lor (Q \land R)
   \]
2. **Second Implication**:  
   \[
   \neg P \rightarrow (\neg Q \land \neg R) \equiv \neg(\neg P) \lor (\neg Q \land \neg R) \equiv P \lor (\neg Q \land \neg R)
   \]

### Step 2: Substitute these into the original expression
The expression now becomes:
\[
(\neg P \lor (Q \land R)) \land (P \lor (\neg Q \land \neg R))
\]

### Step 3: Distribute the conjunction over disjunctions
We expand the expression by applying the distributive property:

1. **Distribute the first term**:  
   \[
   (\neg P \lor (Q \land R)) \equiv (\neg P \lor Q) \land (\neg P \lor R)
   \]
2. **Distribute the second term**:  
   \[
   (P \lor (\neg Q \land \neg R)) \equiv (P \lor \neg Q) \land (P \lor \neg R)
   \]

Now, the overall expression is:
\[
((\neg P \lor Q) \land (\neg P \lor R)) \land ((P \lor \neg Q) \land (P \lor \neg R))
\]

### Step 4: Combine all the conjunctions
This expression is already in the form of a conjunction of disjunctions, which is suitable for PCNF:
\[
\text{PCNF: } (\neg P \lor Q) \land (\neg P \lor R) \land (P \lor \neg Q) \land (P \lor \neg R)
\]

### Step 5: Express the disjunctions as a conjunction of disjunctions (for PDNF)
To find the PDNF, we consider each clause as a separate component and expand the expression to cover all possible combinations where the expression can be true:

\[
\text{PDNF: } (P \land Q \land R) \lor (P \land \neg Q \land \neg R) \lor (\neg P \land Q \land \neg R) \lor (\neg P \land \neg Q \land R)
\]

### Summary:
- **PCNF (Principal Conjunctive Normal Form)**:  
  \[
  (\neg P \lor Q) \land (\neg P \lor R) \land (P \lor \neg Q) \land (P \lor \neg R)
  \]
  
- **PDNF (Principal Disjunctive Normal Form)**:  
  \[
  (P \land Q \land R) \lor (P \land \neg Q \land \neg R) \lor (\neg P \land Q \land \neg R) \lor (\neg P \land \neg Q \land R)
  \]

Would you like any further details or have any questions? 

Here are five related questions:
1. How do we convert a logical expression into its CNF form?
2. Can you explain how the distributive property works in logic?
3. What are the advantages of using CNF and DNF in logic?
4. How does the implication \(P \rightarrow Q\) relate to other logical operations?
5. What is the significance of PCNF and PDNF in boolean algebra and logic simplification?

**Tip:** When converting logical expressions, remember that implications can always be rewritten using disjunctions, which is crucial for simplifying complex expressions into their CNF or DNF forms.

Learn how to find the Principal Conjunctive Normal Form (PCNF) and Principal Disjunctive Normal Form (PDNF) of the logical expression P implies (Q and R) and P not implies (Q and R). Detailed step-by-step solution provided.

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