UGC NET CSE | July 2018 | Part 2 | Question: 79

Question

A knowledge base contains just one sentence, $\exists x \text{ AsHighAs } (x, \text{Everest})$. Consider the following two sentences obtained after applying existential instantiation.

1. AsHighAs (Everest, Everest)
2. AsHighAs (Kilimanjaro, Everest)

Which of the following is correct with respect to the above sentences?

• A. Both sentence a and sentence b are sound conclusions
• B. Both sentence a and sentence b are unsound conclusions
• C. Sentence a is sound but sentence b is unsound
• D. Sentence a is unsound but sentence b is sound

Comments

option d is seems to be correct.

Answer 1

CORRECT
D. Sentence a is unsound but sentence b is sound

Answer 2

The ∃x AsHighAs (x, Everest) means there is one element which is as highest as Everest.

 

a. AsHighAs (Everest, Everest), both are Everest so we can’t compare them.

b. AsHighAs (Kilimanjaro, Everest) means kilimanjaro which is as highest as Everest. So this is a valid statement because we are comparing Kilimanjaro with Everest.

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Answer should be D

Answer 3

A knowledge base contains just one sentence, ∃x AsHighAs (x, Everest). Consider the following two sentences obtained after applying existential instantiation.
(a) AsHighAs (Everest, Everest)
(b) AsHighAs (Kilimanjaro, Everest)
Which of the following is correct with respect to the above sentences ?
(A) Both sentence (a) and sentence (b) are sound conclusions.
(B) Both sentence (a) and sentence (b) are unsound conclusions.
(C) Sentence (a) is sound but sentence (b) is unsound.
(D) Sentence (a) is unsound but sentence (b) is sound.

 

anser C seems to be correct

everest as high as everest

kilimanjaro as hifh as everest