Propositional Logic
When to Use
Use this skill when working on propositional-logic problems in mathematical logic.
Decision Tree
- •
Identify Formula Structure
- •Classify: tautology, contradiction, or contingent?
- •Main connective: AND, OR, IMPLIES, NOT, IFF?
- •
z3_solve.py sat "formula"to check satisfiability
- •
Truth Table Method
- •For small formulas (<=4 variables): enumerate all valuations
- •
sympy_compute.py truthtable "p & (p -> q) -> q" - •Tautology = all T, Contradiction = all F
- •
Natural Deduction
- •Apply inference rules: Modus Ponens, Modus Tollens
- •Conditional proof: assume antecedent, derive consequent
- •
z3_solve.py prove "Implies(And(p, Implies(p,q)), q)"
- •
Semantic Tableaux
- •Build tree by decomposing formula
- •Closed branches = contradictions
- •All branches closed = valid argument
Tool Commands
Z3_Sat
bash
uv run python -m runtime.harness scripts/z3_solve.py sat "And(p, Implies(p, q), Not(q))"
Z3_Tautology
bash
uv run python -m runtime.harness scripts/z3_solve.py prove "Implies(And(p, Implies(p, q)), q)"
Sympy_Truthtable
bash
uv run python -m runtime.harness scripts/sympy_compute.py truthtable "p & (p >> q) >> q"
Z3_Modus_Ponens
bash
uv run python -m runtime.harness scripts/z3_solve.py prove "Implies(And(p, Implies(p,q)), q)"
Cognitive Tools Reference
See .claude/skills/math-mode/SKILL.md for full tool documentation.