MODULE 10
Logic
Propositional through higher-order logic, proof systems, decidability, and the modal, temporal, description and non-classical families.
30 lessons~15h reading
- 0122 min
What Logic Is
BeginnerComing soonArguments, validity versus truth, soundness, and the syntax/semantics distinction that organises the whole module.
- 0228 min
Propositional Logic
BeginnerComing soonAtoms, connectives, well-formed formulas and truth tables, with precedence rules and full truth-table construction.
Assumes: What Logic Is
- 0326 min
Logical Equivalence and Laws
BeginnerComing soonDe Morgan, distribution, contraposition and absorption; simplifying formulas and proving equivalence.
Assumes: Propositional Logic
- 0428 min
Normal Forms: NNF, CNF and DNF
IntermediateComing soonLiterals and clauses, conversion algorithms, the Tseitin transformation, and why CNF is the universal input format.
Assumes: Logical Equivalence and Laws
- 0528 min
Validity, Satisfiability and Entailment
IntermediateComing soonTautology, contradiction and contingency; semantic entailment, and the deduction and refutation theorems.
Assumes: Normal Forms: NNF, CNF and DNF
- 0630 min
Natural Deduction
IntermediateComing soonIntroduction and elimination rules, assumption discharge, and building proofs line by line.
Assumes: Validity, Satisfiability and Entailment
- 0728 min
Axiomatic and Sequent Calculi
AdvancedComing soonHilbert-style systems, Gentzen's sequent calculus, structural rules and cut elimination.
Assumes: Natural Deduction
- 0830 min
Resolution and Refutation
AdvancedComing soonThe resolution rule, unit propagation, refutation completeness, and resolving a clause set by hand.
Assumes: Normal Forms: NNF, CNF and DNF
- 0932 min
SAT and SMT Solvers
AdvancedComing soonThe SAT problem and its NP-completeness, DPLL and CDCL with clause learning, and SMT theories.
Assumes: Resolution and Refutation
- 1030 min
First-Order Logic: Syntax
IntermediateComing soonTerms, constants, functions, predicates, quantifiers, free and bound variables, and scope.
Assumes: Validity, Satisfiability and Entailment
- 1130 min
First-Order Logic: Semantics
AdvancedComing soonStructures, domains, interpretations and variable assignments; the satisfaction relation defined precisely.
Assumes: First-Order Logic: Syntax
- 1228 min
Translating Natural Language to FOL
IntermediateComing soonQuantifier scope ambiguity, restricted quantification, and the standard translation patterns and traps.
Assumes: First-Order Logic: Syntax
- 1330 min
Prenex Form, Skolemisation and Herbrand Universes
AdvancedComing soonMoving quantifiers out, eliminating existentials, and the Herbrand universe, base and theorem.
Assumes: First-Order Logic: Semantics
- 1428 min
Unification
AdvancedComing soonSubstitutions, composition, the most general unifier, the occurs check, and the unification algorithm traced.
Assumes: Prenex Form, Skolemisation and Herbrand Universes
- 1530 min
First-Order Resolution
AdvancedComing soonLifting resolution to FOL, factoring, and refutation proofs over quantified clause sets.
Assumes: Unification
- 1626 min
Forward and Backward Chaining
IntermediateComing soonGeneralised modus ponens, data- versus goal-driven inference, and Horn clause efficiency.
Assumes: Unification
- 1732 min
Soundness, Completeness and Compactness
AdvancedComing soonWhat the metatheorems guarantee, Gödel's completeness theorem, compactness and the Löwenheim–Skolem theorem.
Assumes: First-Order Resolution
- 1834 min
Decidability and the Limits of Logic
AdvancedComing soonDecidable versus semi-decidable, the halting problem, Church–Turing undecidability of FOL, and Gödel's incompleteness theorems.
Assumes: Soundness, Completeness and Compactness
- 1932 min
Second-Order Logic
AdvancedComing soonQuantifying over predicates and relations, the gain in expressive power, characterising the naturals, and the loss of a complete calculus.
Assumes: Decidability and the Limits of Logic
- 2030 min
Higher-Order Logic and Type Theory
AdvancedComing soonSimple type theory, lambda abstraction, Church's formulation, and HOL in interactive theorem provers.
Assumes: Second-Order Logic
- 2132 min
Modal Logic
AdvancedComing soonNecessity and possibility, Kripke frames and accessibility relations, and the K, T, S4 and S5 systems.
Assumes: First-Order Logic: Semantics
- 2230 min
Temporal Logic and Model Checking
AdvancedComing soonLTL and CTL operators, expressing safety and liveness, and model checking as verification.
Assumes: Modal Logic
- 2326 min
Epistemic and Doxastic Logic
AdvancedComing soonReasoning about knowledge and belief, common knowledge, and multi-agent puzzles.
Assumes: Modal Logic
- 2432 min
Description Logics and OWL
AdvancedComing soonConcepts, roles and individuals; the ALC family, TBox and ABox, and the reasoning tasks behind OWL ontologies.
Assumes: First-Order Logic: Semantics
- 2532 min
Horn Clauses and Logic Programming
AdvancedComing soonDefinite clauses, SLD resolution, Prolog execution order, negation as failure, and Datalog for queries.
Assumes: Forward and Backward Chaining
- 2630 min
Non-Monotonic Reasoning
AdvancedComing soonWhy classical entailment cannot retract conclusions; default logic, the closed-world assumption, circumscription and answer set programming.
Assumes: Horn Clauses and Logic Programming
- 2732 min
Many-Valued and Fuzzy Logic
AdvancedComing soonThree-valued and Łukasiewicz systems, fuzzy sets and membership functions, t-norms, and fuzzy inference worked end to end.
Assumes: Propositional Logic
- 2830 min
Intuitionistic and Constructive Logic
AdvancedComing soonRejecting excluded middle, the BHK interpretation, and the Curry–Howard correspondence between proofs and programs.
Assumes: Natural Deduction
- 2930 min
Probabilistic Logic
AdvancedComing soonAttaching probabilities to formulas, Markov logic networks, probabilistic soft logic, and the link to graphical models.
Assumes: First-Order Resolution · Bayes' Theorem
- 3030 min
Logic Meets Machine Learning
AdvancedComing soonNeuro-symbolic architectures, differentiable logic and fuzzy relaxations, inductive logic programming, and using solvers to verify model behaviour.
Assumes: Probabilistic Logic · SAT and SMT Solvers