power point presentation maths tables

1. Unit – I
Fundamentals of Logic

2. • When a mathematician wishes to provide a proof for a given situation, he or she
must use a system of logic. This is also true when a computer scientist develops
the algorithms needed for a program or system of programs.
• The logic of mathematics is applied to decide whether one statement follows
from, or is a logical consequence of, one or more other statements.

3. Basit Connectives and Truth Tables:
• In the development of any mathematical theory, assertions are made in the
form of sentences. Such verbal or written assertions, called statements (or
prepositions), are declarative sentences that are either true or false — but not
both in a particular instance of time.
• For example, the following are statements, and we use the lowercase letters of
the alphabet (such as p, q, and r) to represent these statements.
p: Combinatorics is a required course for sophomores.
q: Margaret Mitchell wrote Gone with the Wind.
r: 2 + 3 = 5.

4. • On the other hand, we do not regard sentences such as the exclamation
“What a beautiful evening!”
or the command
“Get up and do your exercises.”
as statements since they do not have truth values (true or false).
• The preceding statements represented by the letters y, g, and r are
considered to be primitive statements, for there is really no way to break
them down into anything simpler.

5. • New statements can be obtained from existing ones in two ways:
1. Transform a given statement p into the statement ¬p, which denotes its
negation and is read “Not p.”
For the statement p above, ¬p is the statement “Combinatorics is not a required
course for sophomores.” (We do not consider the negation of a primitive
statement to be a primitive statement.)
2. Combine two or more statements into a compound statement, using the
following:
logical connectives:
a) Conjunction: The conjunction of the statements p, q is denoted by p ˄ q,
which is read “p and q.” In our example the compound statement p ˄ q is read
“Combinatorics is a required course for sophomores, and Margaret
Mitchell wrote Gone with the Wind.”

6. b) Disjunction: The expression p V q denotes the disjunction of the statements
p, q and is read “p or q.” Hence “Combinatorics is a required course for
sophomores, or Margaret Mitchell wrote Gone with the Wind” is the verbal
translation for p V q, when y, g are as above. We use the word “or” in the
inclusive sense here.
Consequently, p V q is true if one or the other of p, q is true or if both of
the statements p, g are true. In English we sometimes write “and/or” to point
this out.
The exclusive “or” is denoted by p V q . The compound statement p V q is
true if one or the other of p , q is true but not both of the statements p , q are
true. One way to express p V q for the example here is “Combinatorics is a
required course for sophomores, or Margaret Mitchell wrote Gone with the
Wind, but not both.”

7. c) Implication: We say that “p implies q” and write p → q to designate the
statement, which is the implication of q by p. Alternatively, we can also say
(i) “If p, then q.” (ii) “p is sufficient for q.”
(iii) “p is a sufficient condition for q .” (iv) “q is necessary for p.”
(v) “q is a necessary condition for p,” (vi) “p only if q.”
A verbal translation of p → q for our example is “If combinatorics is
a required course for sophomores, then Margaret Mitchell wrote
Gone with the Wind.”
The statement p is called the hypothesis of the implication; q is
called the conclusion. When statements are combined in this manner,
there need not be any causal relationship between the statements for the
implication to be true.

8. d) Biconditional: Last, the biconditional of two statements p, q is denoted by
p ↔ q, which is read “p if and only if q,” or “p is necessary and sufficient for
q.” For our p, q, “Combinatorics is a required course for sophomores if
and only if Margaret Mitchell wrote Gone with the Wind” conveys the
meaning of p ↔ q. We sometimes abbreviate “p if and only if q” as “p iff q.”
• We must realize that a sentence such as
“The number x is an integer.”
is not a statement because its truth value (true or false) cannot be determined
until a numerical value is assigned for x. If x was assigned the value 7, the
result would be a true statement. Assigning a value such as 1/2 , √2, or Π,
however, would make the resulting statement false.

9. Sr. No. Connective Symbol Compound statement
1
2
3
4
5
AND
OR
NOT
If... then
If and only if (iff)





Conjunction
Disjunction
Negation
Conditional or
implication
Biconditional

10. Operator Precedence
¬ 1
˄ 2
˅ 3
˅ 4
→ 5
↔ 6
Note: To evaluate an expression, the sub expressions that are in braces () evaluated
first then the above precedence next.

11. Truth Table:
• A truth table is a table that specifies the truth values for a primitive or compound
statement.
• It is a combination of rows and columns, in which columns represent individual
input(s) or output(s) variable and its truth values. Similarly rows represent a
header column followed by combination of truth values. Each combination
represents a boolean function.
• A truth table is composed of atleast one input and atleast one output.
• A truth table has a set of inputs followed by set of outputs.
• An input variable has only two possibilities as each input variable represents a
statement. They are true and false. In constructing such truth tables, we write “0”
for false and “1” for true.

12. p (input) ¬p (Output)
0 1
1 0
p q p ˅ q
0 0 0
0 1 1
1 0 1
1 1 1
(i)
(ii)

13. • A truth table has totally 2n rows, whereas n represents total number of input
variables and each row represents a function.
• For example in the truth table (ii) two input variables p and q are there and
hence 22=4 rows.
• If one variable is there 21=2 rows,
three variables 23=8 rows,
four variables 24=16 rows,
five variables 25=32 rows and so on.

14. • From table (i) the boolean functions are p and ¬p
• From table (ii) the boolean functions are
¬p ˅ ¬q,
¬p ˅ q,
p ˅ ¬q,
p ˅ q
• The truth and falsity of the negation and the different kinds of compound
statements on the basis of the truth values of their components.
Boolean function p q p ˅ q
¬p ˅ ¬q 0 0 0
¬p ˅ q 0 1 1
p ˅ ¬q 1 0 1
p ˅ q 1 1 1

15. • The four possible truth assignments for p, q can be listed in any order. The
columns of truth values for p and ¬p are the opposite of each other.
• The statement p ^ q is true only when both p, q are true, whereas p V q is
false only when both the component statements p, q are false. As we noted
before, p ˅ q is true when exactly one of p, q is true.
• The compound statements p ˅ q, p ˅ q are considered true, on the basis of
the truth of their components p, q. This idea of the truth or falsity of a
compound statement being dependent only on the truth values of its
components.

16. p ¬p
0 1
1 0
Truth table for “Not p”
p q p ˅ q
0 0 0
0 1 1
1 0 1
1 1 1
Truth table for “p ˅ q”
p q p ˄ q
0 0 0
0 1 0
1 0 0
1 1 1
Truth table for “p ˄ q”

17. p q p → q
0 0 1
0 1 1
1 0 0
1 1 1
Truth table for “p → q”
p q p ↔ q
0 0 1
0 1 0
1 0 0
1 1 1
Truth table for “p ↔ q”

18. p q p ˅ q
0 0 0
0 1 1
1 0 1
1 1 0
Truth table for “p ˅ q”
p q p ^ q p ˅ q p ˅ q p → q p ↔ q
0 0 0 0 0 1 1
0 1 0 1 1 1 0
1 0 0 1 1 0 0
1 1 1 1 0 1 1
Consolidated truth table for
logical connectives

19. • For the implication p → q, the result is true in all cases except where p is true
and q is false. We do not want a true statement to lead us into believing
something that is false. However, we regard as true a statement such as “If 2 + 3
= 6, then 2 + 4 = 7,” even though the statements “2 + 3 = 6” and “2 + 4 = 7” are
both false.
• Finally, the biconditional p ↔ q is true when the statements p, q have the same
truth value and is false otherwise.

20. Examples
1) Let s, t, and u denote the following primitive statements:
s: Phyllis goes out for a walk.
t: The moon is out.
u: It is snowing.
The following English sentences provide possible translations for the given
(symbolic) compound statements.
a) (t ˄ ¬u)→s : If the moon is out and It is not snowing, then Phyllis goes out for a
walk.
b) t → (¬u → s) : If the moon is out then, if it is not snowing then Phyllis goes out
for a walk.
c) ¬( s ↔ (u ˅ t) ): It is not the case that Phyllis goes out for a walk if and only if it
is snowing or moon is out.

21. 2) Identify the Logical (symbolic) notation for the given English sentence:
a) “Phyllis will go out walking if and only if the moon is out.” : ( s ↔ t )
b) “If it is snowing and the moon is not out, then Phyllis will not go out for a
walk.” : ( u ˄ ¬t ) → ¬s
c) “It is snowing but Phyllis will still go out for a walk.” : ( u ˄ s )
3) Consider the following scenario. It is almost the week before Christmas and
James will be attending several parties that week. Ever conscious of her weight,
she plans not to weigh herself until the day after Christmas. Considering what
those parties may do to her waistline by then, she makes the following
resolution for the December 26 outcome: “If I weigh more than 120 pounds,
then I shall enroll in an exercise class.”

22. Here we let p and q denote the (primitive) statements
p: I weigh more than 120 pounds.
q: I shall enroll in an exercise class.
Then James’s statement (implication) is given by p → q.
Row 1: p and q both have the truth value 0. Here James finds that on December 26
her weight is 120 pounds or less and she does not enroll in an exercise class. She has
not violated her resolution we take her statement p → q to be true and assign it the
truth value 1.
Row 2: p has the truth value 0, q has the truth value 1. This last case finds James
weighing 120 pounds or less on December 26 but still enrolling in an exercise class.
Perhaps her weight is 119 or 120 pounds and she feels this is still too high. Or maybe
she wants to join an exercise class because she thinks it will be good for her health.
No matter what the reason, she has not gone against her resolution q . Once again,
we accept this compound statement as true, assigning it the truth value 1.

23. Row 3: p has the truth value 1, q has the truth value 0. Now that December 26 has
arrived, James finds her weight to be over 120 pounds, but she makes no attempt to
enroI1 in an exercise class. In this case we feel that James has broken her
resolution — in other words, the implication y q is false (and has the truth value 0).
The cases in rows ] and 2 may not immediately agree with our intuition, but the
example should make these results a little easier to accept.
Row 4: p and g both have the truth value 1. On December 26 James finds that she
weighs more than 120 pounds and promptly enrolls in an exercise class, just as she
said she would. Here we consider p — g to be true and assign it the truth value 1.

24. 4) In computer science the if-then and if-then-else decision strictures arise (in
various formats) in high-level programming languages such as Java and C++. The
hypothesis p is often a relational expression such as x > 2. This expression then
becomes a (logical) statement that has the truth value 0 or 1, depending on the value
of the variable x at that point in the program.
The conclusion q is usually an “executable statement.” When dealing with
“if p then q,” in this context, the computer executes q only on the condition that p is
true. For p false, the computer goes to the next instruction in the program sequence.
For the decision structure “if p then q else r,” q is executed when is true and r is
executed when p is false.

25. Start
Read x and y values
If x > 2
?
Then print x value Then print y value
Yes No
Stop

26. 5) Let us examine the truth table for the compound statement “Margaret
Mitchell wrote Gone with the Wind”, and if 2 + 3 ≠ 5, then combinatorics is a
required course for sophomores” .
A) In symbolic notation this statement is written as q ˄ ( ¬r → p), where p, q, and
r represent the primitive statements. The last column of below table contains the
truth values for this result.
We obtained these truth values by using the fact that the conjunction of any two
statements is true if and only if both statements are true.

27. p q r ¬r p ¬r → p q q ˄ (¬r → p)
0 0 0 1 0 0 0 0
0 0 1 0 0 1 0 0
0 1 0 1 0 0 1 0
0 1 1 0 0 1 1 1
1 0 0 1 1 1 0 0
1 0 1 0 1 1 0 0
1 1 0 1 1 1 1 1
1 1 1 0 1 1 1 1

28. 6) Develop the truth tables for the compound statements p ˅ (q ˄ r) and
(p ˅ q) ˄ r .
7) Develop the truth tables for the compound statements p → (p v q) and
statement p ˄ (¬p ˄ q).
p q p p
˅
q
p →
(p ˅
q)
¬p q ¬p ˄
q
p ˄ (¬p ˄
q)
0 0 0 0 1 1 0 0 0
0 1 0 1 1 1 1 1 0
1 0 1 1 1 0 0 0 0
1 1 1 1 1 0 1 0 0
Note: If all the truth values of a statement are true (1), then
the statement is called as tautology. Similarly if all the truth
values are false (0) then the statement is called as
contradiction.

29. 6) Develop the truth tables for the compound statements p ˅ (q ˄ r) and
(p ˅ q) ˄ r .
p q r p ˅ (q ˄ r) (p ˅ q) ˄ r
0 0 0 0 0
0 0 1 0 0
0 1 0 0 0
0 1 1 1 1
1 0 0 1 0
1 0 1 1 1
1 1 0 1 0
1 1 1 1 1

30. 7) The results in columns 4 and 7 of below table reveal that the statement p →
(p v q) is true and that the statement p ˄ (¬p ˄ q) is false for all truth value
assignments for the component statements p, q
p q r p → (p ˅ q) ¬p ¬p ˄ q p ˄ (¬p ˄ q)
0 0 0 1 1 0 0
0 0 1 1 1 0 0
0 1 0 1 1 1 0
0 1 1 1 1 1 0
1 0 0 1 0 0 0
1 0 1 1 0 0 0
1 1 0 1 0 0 0
1 1 1 1 0 0 0

31. • A compound statement is called a tautology if it is true for all truth value
assignments for its component statements. If a compound statement is false for
all such assignments, then it is called a contradiction.
• We shall use the symbol T0 to denote any tautology and the symbol F0 to
denote any contradiction.
• We can use the ideas of tautology and implication to describe what we mean
by a valid argument and it will help us develop needed skills for proving
mathematical theorems.
• In general, an argument starts with a list of given statements called premises
and a statement called the conclusion of the argument.

32. • In general, an argument starts with a list of given statements called as Premises
and the statement called the Conclusion of the argument.
• Premises can be represented as p1, p2,…. ,pn. Similarly q can be used to represent
conclusion. The conclusion q follows logically from the premises.
• Try to show that if each of p1, p2,…. , pn statement is a true statement, then the
statement q is also true.
• The below implication is a way to represent premises - conclusion
(p1˄ p2 ˄…. ˄ pn) → q
hypothesis is the conjunction of the n premises.
• If anyone of the premise is false, irrespective of q value the above implication is
true.
• Similarly if each of premise truth value is 1, then q also have the truth value 1,
then the above implication is a tautology and have a valid argument.

33. Exercises:
Identify how many of the above are primitive statements.

34. 2) Construct truth tables for the following compound statements and verify
its tautology and contradiction property.

35. 3)

36. 4)

37. 5)