Question

Suppose that P(n) is a propositional function. Determine for which improper subset of the domain of n the statement P(n) must be true if a) P(0) is true; for all nonnegative integers n, if P(n) is true, then P(n 2) is true. b) P(0) and P(1) are true; for all nonnegative integers n, if P(n) and P(n 1) are true, then P(n 2) is true

Answer 1

a) P(n) is true for all 'n' in the set ; { 0,2,4,6,8 ….. }

b) P(n) is true for all 'n' in the set ; { 0,1,2,3,4,5 ............ }

Explanation:

a) As P(0) is true

we will assume that

• P(2) is true
• P(4) is true
• P(6) is true

this simply means that ; P(n) is true for all 'n' in the set

{ 0,2,4,6,8 ….. }

b) since P(0) and P(1) are true

we will assume that

• P( 0+2 ) = P(2) is true

also P(1) and P(2) are true

we will assume that

• P(1+2) = P(3) is true

Also from the previous answers it can be seen that P(2) + P(3) is true

we will assume

• P(2+2) = P(4) is true

This simply means that P(n) is true for all 'n' in the set

{ 0,1,2,3,4,5 ............ }