Knowledge

Question 1

agents that reason by operating on internal representations of knowledge.

Answer 1

Knowledge-Based Agents

Question 2

an assertion about the world in a knowledge representation language

Answer 2

Sentence

Question 3

based on propositions, statements about the world that can be either true or false

Answer 3

Propositional Logic

Question 4

letters that are used to represent a proposition.

Answer 4

Propositional Symbols

Question 5

logical symbols that connect propositional symbols in order to reason in a more complex way about the world.

Answer 5

Logical Connectives

Question 6

List all logical connectives:

Answer 6

Not (¬)
And (∧)
Or (∨)
Implication (→)
Biconditional (↔)

Question 7

inverses the truth value of the proposition.

Answer 7

Not

Question 8

connects two different propositions

Answer 8

And

Question 9

is true as as long as either of its arguments is true.

Answer 9

Or

Question 10

represents a structure of “if P then Q.”

Answer 10

Implication

Question 11

In the case of P implies Q (P → Q), P is the ____

Answer 11

Antecedent

Question 12

In the case of P implies Q (P → Q), Q is the ____

Answer 12

Consequent

Question 13

an implication that goes both directions

Answer 13

Biconditional

Question 14

an assignment of a truth value to every proposition.

Answer 14

Model

Question 15

set of sentences known by a knowledge-based agent.

Answer 15

Knowledge Base (KB)

Question 16

a relation that means that if all the information in α is true, then all the information in β is true.

Answer 16

Entailment (⊨)

Question 17

the process of deriving new sentences from old ones.

Answer 17

Inference

Question 18

Define the Model Checking algorithm

Answer 18

To determine if KB ⊨ α
* Enumerate all possible models.
* If in every model where KB is true, α is true as well, then KB entails α (KB ⊨ α).

Question 19

the process of figuring out how to represent propositions and logic in AI

Answer 19

Knowledge Engineering

Question 20

What makes the Model Checking algorithm inefficient?

Answer 20

It has to consider every possible model before giving the answer

Question 21

allows the generation of new information based on existing knowledge without considering every possible model.

Answer 21

Inference Rules

Question 22

if we know an implication and its antecedent to be true, then the consequent is true as well.

Answer 22

Modus Ponens

Question 23

If an And proposition is true, then any one atomic proposition within it is true as well

Answer 23

And Elimination

Question 24

A proposition that is negated twice is true

Answer 24

Double Negation Elimination

Question 25

An implication is equivalent to an Or relation between the negated antecedent and the consequent

Answer 25

Implication Elimination

Question 26

A biconditional proposition is equivalent to an implication and its inverse with an And connective.

Answer 26

Biconditional Elimination

Question 27

It is possible to turn an And connective into an Or connective

Answer 27

De Morgan’s Law

Question 28

A proposition with two elements that are grouped with And or Or connectives can be distributed, or broken down into, smaller units consisting of And and Or

Answer 28

Distributive Property

Question 29

inference rule that states that if one of two atomic propositions in an Or proposition is false, the other has to be true

Answer 29

Resolution

Question 30

two of the same atomic propositions where one is negated and the other is not

Answer 30

Complementary Literals

Question 31

disjunction of literals

Answer 31

Clause

Question 32

consists of propositions that are connected with an Or logical connective

Answer 32

disjunction

Question 33

consists of propositions that are connected with an And logical connective

Answer 33

conjunction

Question 34

conjunction of clauses

Answer 34

Conjunctive Normal Form (CNF)

Question 35

Steps in Conversion of Propositions to Conjunctive Normal Form

Answer 35

* Eliminate biconditionals Turn (α ↔ β) into (α → β) ∧ (β → α). * Eliminate implications Turn (α → β) into ¬α ∨ β. * Move negation inwards until only literals are being negated (and not clauses), using De Morgan’s Laws. Turn ¬(α ∧ β) into ¬α ∨ ¬β

Question 36

Process used when a case where a clause contains the same literal twice is encountered

Answer 36

Factoring

Question 37

process to remove a duplicate literal

Answer 37

Factoring

Question 38

Result after resolving a literal and its negation

Answer 38

empty clause ()

Question 39

Why is an empty clause always false?

Answer 39

it is impossible that both P and ¬P are true

Question 40

Define the resolution algorithm

Answer 40

* To determine if KB ⊨ α: * Check: is (KB ∧ ¬α) a contradiction? * If so, then KB ⊨ α. * Otherwise, no entailment.

Question 41

If our knowledge base is true, and it contradicts ¬α, it means that ¬α is false, and, therefore, α must be true.

Answer 41

Proof by Contradiction

Question 42

Define the proof by contradiction algorithm

Answer 42

To determine if KB ⊨ α: * Convert (KB ∧ ¬α) to Conjunctive Normal Form. * Keep checking to see if we can use resolution to produce a new clause. * If we ever produce the empty clause (equivalent to False), congratulations! We have arrived at a contradiction, thus proving that KB ⊨ α. * However, if contradiction is not achieved and no more clauses can be inferred, there is no entailment.

Question 43

logic that allows us to express more complex ideas more succinctly than propositional logic

Answer 43

First Order Logic

Question 44

Types of symbols used by first order logic:

Answer 44

Constant Symbols & Predicate Symbols

Question 45

these symbols represent objects

Answer 45

Constant Symbols

Question 46

these symbols are like relations or functions that take an argument and return a true or false value

Answer 46

Predicate Symbols

Question 47

tool that can be used in first order logic to represent sentences without using a specific constant symbol

Answer 47

Universal Quantification

Question 48

used to create sentences that are true for at least one x

Answer 48

Existential Quantification