- •Contents
- •Preface
- •1 Introduction
- •1.1 Issues of Vagueness
- •1.3 The Problem of the Fringe
- •1.4 Preview of the Rest of the Book
- •1.5 History and Scope of Fuzzy Logic
- •1.6 Tall People
- •1.7 Exercises
- •2 Review of Classical Propositional Logic
- •2.1 The Language of Classical Propositional Logic
- •2.2 Semantics of Classical Propositional Logic
- •2.3 Normal Forms
- •2.4 An Axiomatic Derivation System for Classical Propositional Logic
- •2.5 Functional Completeness
- •2.6 Decidability
- •2.7 Exercises
- •3.2 Semantics of Classical First-Order Logic
- •3.3 An Axiomatic Derivation System for Classical First-Order Logic
- •3.4 Exercises
- •4.1 Numeric Truth-Values for Classical Logic
- •4.2 Boolean Algebras and Classical Logic
- •4.3 More Results about Boolean Algebras
- •4.4 Exercises
- •5.2 Lukasiewicz’s Three-Valued Logic
- •5.3 Bochvar’s Three-Valued Logics
- •5.5 Normal Forms
- •5.7 Lukasiewicz’s System Expanded
- •5.8 Exercises
- •6.3 Exercises
- •7.3 Tautologies, Validity, and “Quasi-”Semantic Concepts
- •7.4 Exercises
- •8.3 Exercises
- •9.3 MV-Algebras
- •9.4 Exercises
- •11 Fuzzy Propositional Logics: Semantics
- •11.1 Fuzzy Sets and Degrees of Truth
- •11.2 Lukasiewicz Fuzzy Propositional Logic
- •11.3 Tautologies, Contradictions, and Entailment in Fuzzy Logic
- •11.4 N-Tautologies, Degree-Entailment, and N-Degree-Entailment
- •11.5 Fuzzy Consequence
- •11.7 T-Norms, T-Conorms, and Implication in Fuzzy Logic
- •11.9 Product Fuzzy Propositional Logic
- •11.10 Fuzzy External Assertion and Negation
- •11.11 Exercises
- •12 Fuzzy Algebras
- •12.2 Residuated Lattices and BL-Algebras
- •12.3 Zero and Unit Projections in Algebraic Structures
- •12.4 Exercises
- •13 Derivation Systems for Fuzzy Propositional Logic
- •13.1 An Axiomatic System for Tautologies and Validity in Fuzzy
- •13.2 A Pavelka-Style Derivation System for Fuzzy
- •13.3 An Alternative Axiomatic System for Tautologies and Validity in FuzzyL Based on BL-Algebras
- •13.7 External Assertion Axioms
- •13.8 Exercises
- •14.1 Fuzzy Interpretations
- •14.2 Lukasiewicz Fuzzy First-Order Logic
- •14.3 Tautologies and Other Semantic Concepts
- •14.4 Lukasiewicz Fuzzy Logic and the Problems of Vagueness
- •14.6 Product Fuzzy First-Order Logic
- •14.8 Exercises
- •15.3 An Axiomatic Derivation System for Fuzzy
- •15.4 Combining Fuzzy First-Order Logical Systems; External Assertion
- •15.5 Exercises
- •16 Extensions of Fuzziness
- •16.2 Fuzzy “Linguistic” Truth-Values
- •16.3 Other Fuzzy Extensions of Fuzzy Logic
- •16.4 Exercises
- •17 Fuzzy Membership Functions
- •17.2 Empirical Construction of Membership Functions
- •17.3 Logical Relevance?
- •17.4 Exercises
- •Bibliography
- •Index
Index
–, 59 |
algebraic semantics, 61 |
fuzzy, 242 |
!, 219 |
algebraic sum, 196 |
strongly, 26 |
¬, 12 |
ambiguous, 6 |
weakly, 26 |
, 12 |
antecedent, 13 |
conditional, 12 |
, 12 |
antisymmetric, 68 |
conjunction, 12 |
→, 12 |
argument, 17 |
bold, 94–95 |
↔, 12 |
arity, 39 |
weak, 94 |
, 39 |
associative, 60 |
Conjunction Introduction |
, 39 |
axiom schema, 22 |
(CI), 150, 156 |
, 60 |
derived, 28 |
connective |
∩, 60 |
instance of, 22 |
binary, 12 |
, 94 |
|
defined, 15 |
, 204 |
Baaz, Matthias, 204 |
main, 13 |
, 204 |
Baaz delta operation, 204 |
normal, 73 |
α, 219 |
BE3, 82 |
primitive, 15 |
=def, 15 |
BE3 , 139 |
truth-functional, 13 |
&, 94 |
BEA, 166 |
unary, 12 |
[0. .1], 178 |
BI3, 80 |
uniform, 73 |
|=, 75 |
BI3 , 138 |
consequent, 13 |
, 60 |
BIA, 166 |
Consequent Value (CV), 238 |
, 59 |
biconditional, 12 |
Conservative Extension |
, 59 |
binding priority, 12 |
Theorem for FLPA, 244 |
1-projection, 204 |
BLA, 245 |
constant, 39 |
|
Black, Max, 2, 4, 5n6, 309 |
continuous function, 193 |
absorption, 60 |
BLG A, 294–295 |
contradiction, 15, 47, 75, 180, |
adequate derivation system, |
BLGA, 249 |
266 |
26 |
BLLA, 249 |
n-, 184 |
adjointness condition, 197 |
BLPA, 252 |
quasi-, 87, 141 |
adjunct residuum, 198 |
Bochvar, Dmitri, 80, 82 |
Contraposition (CON), 104, |
algebra |
Bold Conjunction |
123 |
BL-, 216 |
Introduction (BCI), 233 |
countable, 315 |
Boolean, 60 |
borderline, 1, 5 |
counterextension, 130 |
DeMorgan, 164 |
CL A, 49–51 |
crisp set, 177 |
Godel,¨ 218 |
|
|
Heyting, 218 |
CLA, 22 |
decidable, 35–36 |
Kleene, 165 |
clause, 20 |
decision procedure, 35 |
Lindenbaum, 68 |
commutative, 60 |
Deduction Theorem |
MV-, 167, 212 |
compact, 228 |
for BLGA, 251 |
product, 218 |
fuzzy, 243 |
for CLA, 24 |
unit projection, 219 |
complementation, 60 |
Modified, for BLPA, 253 |
algebraic interpretation, 61 |
complete, 26 |
Modified, for FLA, 228 |
algebraic product, 196 |
functionally, 32–35 |
Modified, for L3A, 114 |
327
328 |
Index |
definitely operator, 306 |
formula of propositional |
L3, 76 |
|
|
degree |
logic, 13 |
L3 , 131 |
|
|
of membership, 177 |
atomic, 13 |
L3 A, 146 |
|
|
of truth, 178 |
compound, 13 |
L3 PA, 153–154 |
||
degree-entailment, 88, 142, |
Frege, Gottlob, 22 |
L3A, 100 |
|
|
186, 267 |
fringe, 1, 5, 130 |
L3MV, 167 |
|
|
degree-validity, 88, 142, 186, |
higher-order, 175 |
L3PA, 115–117 |
||
267 |
fuzzy consequence, 190 |
lattice, 65 |
|
|
DeMorgan’s Law, 19 |
fuzzy logic in the broad sense, |
bounded, 65 |
||
derivable, 23 |
9–10 |
complemented, 65 |
||
to degree n, 241 |
fuzzy logic in the narrow |
distributed, 65 |
||
to degree v, 121 |
sense, 8 |
residuated, 214 |
||
derivation, 23 |
fuzzy set, 177 |
semi-, 166 |
|
|
derivation system |
FuzzyBE, 193 |
lattice ordering relation, 68 |
||
axiomatic, 21 |
FuzzyBI, 192 |
Law of Excluded Middle, 3 |
||
natural deduction, 21n5 |
FuzzyG, 200 |
Law of Noncontradiction, 7, |
||
derived rule, 28 |
FuzzyG , 278 |
16 |
|
|
designated truth-value, 85 |
FuzzyGL, 216 |
least upper bound, 184 |
||
disjunction, 12 |
FuzzyK, 192 |
Left Conjunct Simplification |
||
bold, 94–95 |
FuzzyL, 179 |
(LSIMP), 104 |
||
Disjunctive Consequence |
FuzzyL , 263 |
linguistic truth-value, 303 |
||
(DC), 112, 234 |
FuzzyP, 202 |
literal, 18 |
|
|
Disjunctive Syllogism (DS), |
FuzzyP , 280 |
complementary, 20 |
||
111 |
FuzzyPL, 216 |
LKL, |
164 |
|
distribution, 60 |
|
LKL , 165 |
|
|
domain, 41, 60 |
general, 6 |
lower bound, 183 |
||
Double Negation (DN), 108 |
Generalized Contraposition |
greatest, 183 |
||
downward distance, 187 |
(GCON), 108 |
lub, 184 |
|
|
maximum, 188 |
Generalized Hypothetical |
Lukasiewicz, |
Jan, 8, 21, 76, 78, |
|
dual, 66 |
Syllogism (GHS), 109 |
179n6, 223 |
||
dual t-norm, t-conorm pair, |
Generalized Modus Ponens |
|
|
|
196 |
(GMP), 109 |
McNaughton, Robert, 193 |
||
|
Godel,¨ Kurt, 200n20 |
McNaughton’s Theorem, 193 |
||
entailment, 17, 48, 75, 180, |
Goguen, Joseph, 3, 8n5, |
meet, 60 |
|
|
266 |
202n24, 309 |
bold, 169 |
|
|
degree-, 88, 142, 186, 267 |
graded formula, 115 |
Modified Constructive |
||
n-degree-, 188, 267 |
greatest lower bound, 183 |
Dilemma (MCD), 111, |
||
quasi-, 87, 141 |
|
125 |
|
|
equivalence, 16 |
Hajek,´ Petr, 9, 216n4, 245 |
Modus Ponens (MP), 22, |
||
express a truth-function, 33 |
hedge, 300 |
116–117, 231 |
||
extension, 130 |
Hypothetical Syllogism (HS), |
Modus Tollens, 31 |
||
extension of a predicate, 43 |
28, 123, 233 |
|
|
|
external assertion, 82 |
|
n-contradiction, 184 |
||
fuzzy, 204 |
idempotent, 60 |
n-degree-entailment, 188, |
||
External Assertion (EA), 297 |
implication, 197 |
267 |
|
|
|
interpretation, 43, 130, |
n-degree-validity, 188, 267 |
||
first-order logic, 39 |
262 |
negation, 12 |
|
|
FL PA, 288–289 |
classical, 140 |
external, 82 |
||
FLA, 223 |
|
involutive, 203 |
||
FLPA, 230–231 |
join, 60 |
New Problem of the Fringe, |
||
formula of first-order logic, |
bold, 169 |
174 |
|
|
40 |
|
normal, 140 |
|
|
atomic, 40 |
Kleene, Stephen, 71, 74 |
normal form, 18–21 |
||
closed, 41 |
KS3, 71 |
conjunctive, 20 |
||
compound, 40 |
KS3 , 138 |
disjunctive, 18 |
Index |
|
329 |
Normality Lemma, 75 |
RFuzzyL, 230 |
Truth-value Constant |
First-order, 140 |
R-implication, 199 |
Introduction (TCI), 117, |
Novak,´ Vilem,´ 9, 288n3 |
Russell, Bertrand, 2 |
231 |
n-tautology, 183, 267 |
|
|
|
satisfaction, 44 |
uncountable, 316 |
orthocomplement, 164 |
satisfiable, 228 |
unit element, 60 |
|
semantics |
unit interval, 178 |
Pavelka, Jan, 8, 114n9 |
of first-order logic, 42 |
unit projection, 219 |
phrase, 18 |
propositional logic, 15 |
universal closure, 152 |
precise, 1, 5 |
semi-decidable, 55 |
Universal Generalization |
predicate, 39 |
set |
(UG), 51, 289 |
prelinearity condition, 218n5 |
crisp, 177 |
Universal Generalization in |
Principle of Bivalence, 1 |
fuzzy, 177 |
the Consequent (UGC), |
Principle of Charity, 4 |
Sorites paradox, 3–5 |
149 |
Principle of Double Negation, |
sound, 26 |
Universal Instantiation (UI), |
7 |
fuzzy, 241 |
53 |
Problem of the Fringe, 6–7 |
Substitution (SUB), 106 |
upper bound, 184 |
proof, 24 |
substitution instance, 51 |
least, 184 |
propositional logic, 12 |
|
|
|
tautology, 15, 47, 74, 180, |
vague, 1, 5–6 |
Q-implication, 199 |
266 |
validity, 17, 48, 75, 267 |
quantifier |
BA-, 61 |
decaying, 271 |
existential, 39, 40 |
MV-, 171, 213 |
degree-, 88, 143, 186, |
universal, 39, 40 |
n-, 183, 267 |
267 |
quasi-contradiction, 87, 141 |
quasi-, 85, 141 |
n-degree, 188 |
quasi-entailment, 87, 141 |
t-conorm, 95 |
quasi-, 87, 141 |
quasi-tautology, 85, 141 |
term, 39 |
Value Summary (VS), 239 |
quasi-validity, 87, 141 |
theorem, 24 |
variable, 39 |
|
to degree n, 241 |
bound occurrence, 40 |
RealFLPA, 244 |
to degree v, 120 |
free occurrence, 40 |
RealFuzzyL, 244 |
t-norm, 95 |
variable assignment, 44 |
recursively axiomatizable, |
transitive, 68 |
x-variant of, 44 |
287 |
Transposition (TRAN), 29, |
|
reflexive, 68 |
108 |
Weak Conjunction |
regular, 92 |
truth-function, 32 |
Introduction (WCI), |
relative, 6 |
truth-preserving, 4 |
234 |
residuation operation, 197 |
truth-table, 14–15 |
|
adjunct, 198 |
truth-value assignment, 14 |
Zadeh, Lotfi, 8, 10, 303 |
residuum |
classical, 75 |
zero element, 60 |
adjunct, 198 |
consonant, 190 |
zero projection, 219 |