Lecture 3

Question 1

what is knowledge representation scheme?

Answer 1

role is to abstract out critical features of a problem domain, make the info available to problem solving scheme

Question 2

what is the advantage of using logic as a representation formalism?

Answer 2

it comes with methods for reasoning from knowledge. we can use this reasoning to infer new knowledge

Question 3

what are the 3 main components in logic?

Answer 3

• syntax - defines legal expressions
• semantics - defines meanings of a sentence in terms of truth
• inference mechanism - a procedure of determining what follows (validity) from a set of logical sentences

Question 4

what is a propositional statement?

Answer 4

a statement that an be evaluated as true or false, eg 7 + 6 = 12, bobs car is blue. some examples of things that aren’t propositional are 7 + 4 and jakes uncle

Question 5

what are propositional symbols?

Answer 5

propositional symbols - P, Q, R, S, …
truth symbols - true, false
connectives - ^ (down arrow, not symbol(corner of box), implies and 3 equal sign)

Question 6

what is a propositional sentence?

Answer 6

true, flase, P, Q, R, S, … are sentences and any connectives can go between them (see propositional symbos)

Question 7

what is a wff?

Answer 7

is a propositional sentence

Question 8

what is a tautology and contradiction?

Answer 8

tautology - everything is true

contradiction - everything is flase

Question 9

limitations of propositional logic

Answer 9

everything is either T or F, cant represent nemo is dead and nemo is white without 2 propositions (no way to access components of the proposition)