Chapter 3 Flashcards
statement
a statement is a declarative sentence that is either true or false but not both at the same time
simple statement
a statement that conveys a single idea
compound statement
a statement that conveys more than one idea (2+)
Logical connectives meaning ~ Λ V --> ↔
~ = not Λ = and V = or --> = if, then ↔ = if and only if
symbolic forms not p p and q p or q if p, then q p iff q
~p p Λ q p V q p --> q p ↔ q
Type of logical connective ~ Λ V --> ↔
~ = negation Λ = conjunction V = disjunction --> = conditional ↔ = biconditional
Truth value of a simple statement
the truth value of a simple statement is either true or false
truth value of a compound statement
the truth value of a compound statement depends on the truth values of the simple statements and logical connectives used to form the compound statement
Truth table
a table used to show the truth value of a compound statement for all possible truth values (and combination of truth values) for its simple statements
Truth Table for Negations
p ~p
T F
F T
Negate the following:
My house is blue
My house is not blue
Negate the following:
Canada is not a country
Canada is a country
Write the following in symbolic form:
Today is not Friday and it is not raining
~ F Λ ~ R
Write the following in symbolic form:
If it is not raining, then today is not Friday and I am not going to a movie
~ R –> (~F Λ ~ M)
Write the following in words:
R Λ F
It is raining and today is Friday.
~ M V B
I am not going to a movie or i am going to a baseball game
B ↔ ~F
I am not going to a baseball game if and only if today is not Friday.
(F Λ ~R) –> (M V B)
If today is Friday and it is not raining, then I am going to the movies or I am going to the baseball game.
~ (M V R)
It is not the case that I am going to a movie or it is raining.
Truth table for conjunctions
p q p Λ q T T T T F F F T F F F F
Truth table for conjunctions
p q p Λ q T T T T F F F T F F F F
Both simple statements must be true in order to get a true conjuction
Truth table for disjunctions
p q p V q T T T T F T F T T F F F
One or the other (or both) must be true in order to get a true disjunction
Quantifiers (Negate them) All X are Y No X are Y Some X are not Y Some X are Y
Some X are not Y
Some X are Y
All X are Y
All X are not Y or No X are Y
Negate the following:
All bears are brown
Some bears are not brown
Negate the following:
No man is an island
Some man is an island
Negate the following:
Some vegetables are not green
All vegetables are green