Tautology Contradiction
1. The problem asks to identify whether $[(p \to q) \lor (q \to r) \lor (r \to p)]$ is a tautology, contradiction, or contingency.
2. The problem also asks to identify whether $[((p \lor q) \lor r) \land ((\neg p \land \neg q) \land \neg r)]$ is a tautology, contradiction, or contingency.
**Step 1**: Recall the definitions:
- A **tautology** is true in every possible truth assignment.
- A **contradiction** is false in every possible truth assignment.
- A **contingency** is true in some truth assignments and false in others.
**Step 2**: Analyze statement 1: $[(p \to q) \lor (q \to r) \lor (r \to p)]$
- Implication $p \to q$ is false only if $p$ is true and $q$ is false.
- We want to check if this disjunction is true for all truth assignments of $p,q,r$.
Construct truth table variables (values of $p,q,r$) and determine $p \to q$, $q \to r$, and $r \to p$; then their disjunction:
| $p$ | $q$ | $r$ | $p \to q$ | $q \to r$ | $r \to p$ | Disjunction |
|-----|-----|-----|-----------|-----------|-----------|-------------|
| T | T | T | T | T | T | T |
| T | T | F | T | F | F | T |
| T | F | T | F | T | T | T |
| T | F | F | F | T | F | T |
| F | T | T | T | T | T | T |
| F | T | F | T | F | T | T |
| F | F | T | T | T | T | T |
| F | F | F | T | T | T | T |
Since the disjunction is true in all cases, statement 1 is a **tautology**.
**Step 3**: Analyze statement 2:
$[((p \lor q) \lor r) \land ((\neg p \land \neg q) \land \neg r)]$
Breaking down:
- Left part $(p \lor q) \lor r$ is true if at least one of $p,q,r$ is true.
- Right part $(\neg p \land \neg q) \land \neg r$ means all $p,q,r$ are false.
We have a conjunction of these parts, so both must be true simultaneously.
Check if possible:
- Left: at least one true
- Right: all false
This is impossible.
Hence statement 2 is always false: a **contradiction**.
**Final answer:**
1. $[(p \to q) \lor (q \to r) \lor (r \to p)]$ is a tautology.
2. $[((p \lor q) \lor r) \land ((\neg p \land \neg q) \land \neg r)]$ is a contradiction.