2. What is Propositional Logic?
• A proposition(statement) is declarative sentence in which is either true or false.
𝐸𝑥𝑎𝑚𝑝𝑙𝑒:
10+15=25
18>5
𝑀𝑎𝑘𝑎𝑡𝑖𝑖𝑠 h
𝑡 𝑒𝑃𝑎𝑟𝑡 𝑜𝑓 𝑉𝑖𝑠𝑎𝑦𝑎𝑠.
𝐹 𝑖𝑛 𝐴𝐹𝑃𝑚𝑒𝑎𝑛𝑠F𝑜𝑙𝑙𝑜𝑤 .
𝑃𝑙𝑒𝑎𝑠𝑒,𝑠𝑡𝑎𝑛𝑑.
h
𝑊 𝑒𝑟𝑒𝑑𝑜 𝑦𝑜𝑢𝑙𝑖𝑣𝑒?
𝑇𝑟𝑢𝑒
𝑇𝑟𝑢𝑒
𝐹𝑎𝑙𝑠𝑒
𝐹𝑎𝑙𝑠𝑒
𝑁𝑜𝑡 𝑠𝑡𝑎𝑡𝑒𝑚𝑒𝑛𝑡 .
𝑁𝑜𝑡𝑠𝑡𝑎𝑡𝑒𝑚𝑒𝑛𝑡.
3. 5 Basic Logic Connectives
• 1. Negation (~)
• If p is a proposition, then negation of p is a proposition which is-
𝑇𝑟𝑢𝑒 h
𝑤 𝑒𝑛𝑝 𝑖𝑠 𝑓𝑎𝑙𝑠𝑒.
𝐹𝑎𝑙𝑠𝑒 h
𝑤 𝑒𝑛𝑝 𝑖𝑠𝑡𝑟𝑢𝑒.
h
𝑇𝑟𝑢𝑡 𝑇𝑎𝑏𝑙𝑒
P ~P
F T
T F
F T
𝑆𝑒𝑛𝑡𝑒𝑛𝑐𝑒:
𝐼𝑓 h
𝑡 𝑒𝑠𝑡𝑎𝑡𝑒𝑚𝑒𝑛𝑡 𝑝𝑖𝑠:𝐼𝑡 𝑠 𝑐𝑙𝑜𝑢𝑑𝑦 𝑜𝑢𝑡𝑠𝑖𝑑𝑒.
h
𝑇 𝑒𝑛 h
𝑡 𝑒𝑛𝑒𝑔𝑎𝑡𝑖𝑜𝑛𝑖𝑠: 𝐼𝑡 𝑠 𝑁𝑂𝑇 𝑐𝑙𝑜𝑢𝑑𝑦 𝑜𝑢𝑡𝑠𝑖𝑑𝑒 .
4. • 2. Conjunction ( ^ )
𝐼𝑓 𝑝 𝑎𝑛𝑑𝑞𝑎𝑟𝑒𝑡𝑤𝑜𝑝𝑟𝑜𝑝𝑜𝑠𝑖𝑡𝑖𝑜𝑛𝑠 , h
𝑡 𝑒𝑛𝑐𝑜𝑛𝑗𝑢𝑛𝑐𝑡𝑖𝑜𝑛𝑜𝑓 𝑝 𝑎𝑛𝑑𝑞𝑖𝑠𝑝𝑟𝑜𝑝𝑜𝑠𝑖𝑡𝑖𝑜𝑛 h h
𝑤 𝑖𝑐 𝑖𝑠
−𝑇𝑟𝑢𝑒 h
𝑤 𝑒𝑛 h
𝑏𝑜𝑡 𝑝𝑎𝑛𝑑𝑞 𝑎𝑟𝑒𝑡𝑟𝑢𝑒
h
𝑇𝑟𝑢𝑡 𝑇𝑎𝑏𝑙𝑒 P Q P ^ Q
T T T
T F F
F F F
F T F
𝑆𝑒𝑛𝑡𝑒𝑛𝑐𝑒
:
𝑝: 3+7=10
𝑞:𝐼𝑡 𝑠 𝑐𝑙𝑜𝑢𝑑𝑦 𝑜𝑢𝑡𝑠𝑖𝑑𝑒.
h
𝑇 𝑒𝑛,𝑐𝑜𝑛𝑗𝑢𝑛𝑐𝑡𝑖𝑜𝑛𝑜𝑓 𝑝 𝑎𝑛𝑑𝑞𝑖𝑠
(p ^ q) = 3 + 7 = 10 and it`s cloudy outside
5. 3. Disjunction (V)
𝐼𝑓 𝑝𝑎𝑛𝑑𝑞𝑎𝑟𝑒𝑡𝑤𝑜𝑝𝑟𝑜𝑝𝑜𝑠𝑖𝑡𝑖𝑜𝑛𝑠, h
𝑡 𝑒𝑛𝑑𝑖𝑠𝑗𝑢𝑛𝑐𝑡𝑖𝑜𝑛𝑜𝑓 𝑝𝑎𝑛𝑑𝑞𝑖𝑠𝑎𝑝𝑟𝑜𝑝𝑜𝑠𝑖𝑡𝑖𝑜𝑛 h h
𝑤 𝑖𝑐 𝑖𝑠:
−𝑇𝑟𝑢𝑒 h
𝑤 𝑒𝑛 h
𝑒𝑖𝑡 𝑒𝑟 𝑜𝑛𝑒𝑜𝑓 𝑝𝑜𝑟 𝑞𝑜𝑟 h
𝑏𝑜𝑡 𝑎𝑟𝑒𝑡𝑟𝑢𝑒
h
𝑇𝑟𝑢𝑡 𝑇𝑎𝑏𝑙𝑒 p q p v q
T F T
F T T
T T T
F F F
𝑆𝑒𝑛𝑡𝑒𝑛𝑐𝑒:
𝐼𝑓 𝑝 𝑎𝑛𝑑𝑞𝑎𝑟𝑒𝑝𝑟𝑜𝑝𝑜𝑠𝑖𝑡𝑖𝑜𝑛 h
𝑤 𝑒𝑟𝑒:
𝑝: 3+10=13
𝑞: 𝐼𝑡 𝑖𝑠𝑐𝑙𝑜𝑢𝑑𝑦 𝑜𝑢𝑡𝑠𝑖𝑑𝑒.
h
𝑇 𝑒 𝑑𝑖𝑠𝑗𝑢𝑛𝑐𝑡𝑖𝑜𝑛𝑜𝑓 h
𝑡 𝑖𝑠𝑝𝑎𝑛𝑑𝑞 𝑖𝑠:
𝑝𝑉 𝑞:3+10=13𝑜𝑟 𝐼𝑡 𝑖𝑠𝑐𝑙𝑜𝑢𝑑𝑦𝑜𝑢𝑡𝑠𝑖𝑑𝑒.
6. 4. Conditional ()
𝑃𝑟𝑜𝑝𝑜𝑠𝑖𝑡𝑖𝑜𝑛𝑎𝑙𝑜𝑓 h
𝑡 𝑒𝑡𝑦𝑝𝑒 if p then q 𝑖𝑠𝑐𝑎𝑙𝑙𝑒𝑑𝑎𝑐𝑜𝑛𝑑𝑖𝑡𝑖𝑜𝑛𝑎𝑙𝑜𝑟 𝑖𝑚𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛𝑝𝑟𝑜𝑝𝑜𝑠𝑖𝑡𝑖𝑜𝑛.
−𝐼𝑡 𝑖𝑠𝑡𝑟𝑢𝑒 h
𝑤 𝑒𝑛 h
𝑏𝑜𝑡 𝑝 𝑎𝑛𝑑𝑞𝑎𝑟𝑒𝑡𝑟𝑢𝑒.
−𝐼𝑡 𝑖𝑠𝑡𝑟𝑢𝑒 h
𝑤 𝑒𝑛𝑝𝑖𝑠 𝑓𝑎𝑙𝑠𝑒.
h
𝑇𝑟𝑢𝑡 𝑇𝑎𝑏𝑙𝑒 p q P q
T T T
T F F
F T T
T T T
𝑆𝑒𝑛𝑡𝑒𝑛𝑐𝑒:
𝑝: 6+15=21
𝑞:22>20
(𝑝→𝑞): 𝐼𝑓 6+15=21, h
𝑡 𝑒𝑛,22>20.
7. 5. Biconditional ( )
𝑃𝑟𝑜𝑝𝑜𝑠𝑖𝑡𝑖𝑜𝑛𝑜𝑓 h
𝑡 𝑒𝑡𝑦𝑝𝑒 − −
𝑝 𝑖𝑓 𝑛𝑎𝑑 𝑜𝑛𝑙𝑦 𝑖𝑓 𝑞 𝑖𝑠 𝑐𝑎𝑙𝑙𝑒𝑑 𝑏𝑖 𝑐𝑜𝑛𝑑𝑖𝑡𝑖𝑜𝑛𝑎𝑙 𝑜𝑟 𝑏𝑖 𝑖𝑚𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛 𝑝𝑟𝑜𝑝𝑜𝑠𝑖𝑡𝑖𝑜𝑛
−𝐼𝑡 𝑖𝑠𝑡𝑟𝑢𝑒 h
𝑤 𝑒𝑛 h
𝑒𝑖𝑡 𝑒𝑟 h
𝑏𝑜𝑡 𝑝 𝑎𝑛𝑑𝑞𝑎𝑟𝑒𝑡𝑟𝑢𝑒.
−𝐼𝑡 𝑖𝑠𝑡𝑟𝑢𝑒 h
𝑤 𝑒𝑛 h
𝑏𝑜𝑡 𝑝 𝑎𝑛𝑑𝑞𝑎𝑟𝑒 𝑓𝑎𝑙𝑠𝑒.
. p q (p q)
T F F
T F F
F T F
F F T
𝑆𝑒𝑛𝑡𝑒𝑛𝑐𝑒:
𝑝: 7+21=28
𝑞:21<28<30
(𝑝<−→ 𝑞) :7+21=28 𝑖𝑓 𝑎𝑛𝑑 𝑜𝑛𝑙𝑦 𝑖𝑓 21<28<30.
8. Try to answer this:
1. ( 𝑃 𝑉 𝑅) 𝑄
2. ( 𝑝𝑟
)→ ( 𝑞 𝑉 𝑝 )
P Q R
F T T
F T F
T T T
F F F
T F F
T F T
9. 3 .( 𝑃 𝑉 𝑅) 𝑄
P Q R ~P ~Q ~R (~P V ~R)
F T T
F T F
T T T
F F F
T F F
T F T
10. [ ( 𝑃 → 𝑄) 𝑉 (𝑄 𝑅 )]( 𝑃 𝑉 𝑅)
𝐺𝑖𝑣𝑒𝑛:
P Q R ~Q (P ~Q) ~R (Q ^ ~R) ~P (~P V ~R)
T F T
F F T
T T F