Skip to content
VibeFormer

MODULE 10

Logic

Propositional through higher-order logic, proof systems, decidability, and the modal, temporal, description and non-classical families.

30 lessons~15h reading

  1. 01

    What Logic Is

    BeginnerComing soon

    Arguments, validity versus truth, soundness, and the syntax/semantics distinction that organises the whole module.

    22 min
  2. 02

    Propositional Logic

    BeginnerComing soon

    Atoms, connectives, well-formed formulas and truth tables, with precedence rules and full truth-table construction.

    Assumes: What Logic Is

    28 min
  3. 03

    Logical Equivalence and Laws

    BeginnerComing soon

    De Morgan, distribution, contraposition and absorption; simplifying formulas and proving equivalence.

    Assumes: Propositional Logic

    26 min
  4. 04

    Normal Forms: NNF, CNF and DNF

    IntermediateComing soon

    Literals and clauses, conversion algorithms, the Tseitin transformation, and why CNF is the universal input format.

    Assumes: Logical Equivalence and Laws

    28 min
  5. 05

    Validity, Satisfiability and Entailment

    IntermediateComing soon

    Tautology, contradiction and contingency; semantic entailment, and the deduction and refutation theorems.

    Assumes: Normal Forms: NNF, CNF and DNF

    28 min
  6. 06

    Natural Deduction

    IntermediateComing soon

    Introduction and elimination rules, assumption discharge, and building proofs line by line.

    Assumes: Validity, Satisfiability and Entailment

    30 min
  7. 07

    Axiomatic and Sequent Calculi

    AdvancedComing soon

    Hilbert-style systems, Gentzen's sequent calculus, structural rules and cut elimination.

    Assumes: Natural Deduction

    28 min
  8. 08

    Resolution and Refutation

    AdvancedComing soon

    The resolution rule, unit propagation, refutation completeness, and resolving a clause set by hand.

    Assumes: Normal Forms: NNF, CNF and DNF

    30 min
  9. 09

    SAT and SMT Solvers

    AdvancedComing soon

    The SAT problem and its NP-completeness, DPLL and CDCL with clause learning, and SMT theories.

    Assumes: Resolution and Refutation

    32 min
  10. 10

    First-Order Logic: Syntax

    IntermediateComing soon

    Terms, constants, functions, predicates, quantifiers, free and bound variables, and scope.

    Assumes: Validity, Satisfiability and Entailment

    30 min
  11. 11

    First-Order Logic: Semantics

    AdvancedComing soon

    Structures, domains, interpretations and variable assignments; the satisfaction relation defined precisely.

    Assumes: First-Order Logic: Syntax

    30 min
  12. 12

    Translating Natural Language to FOL

    IntermediateComing soon

    Quantifier scope ambiguity, restricted quantification, and the standard translation patterns and traps.

    Assumes: First-Order Logic: Syntax

    28 min
  13. 13

    Prenex Form, Skolemisation and Herbrand Universes

    AdvancedComing soon

    Moving quantifiers out, eliminating existentials, and the Herbrand universe, base and theorem.

    Assumes: First-Order Logic: Semantics

    30 min
  14. 14

    Unification

    AdvancedComing soon

    Substitutions, composition, the most general unifier, the occurs check, and the unification algorithm traced.

    Assumes: Prenex Form, Skolemisation and Herbrand Universes

    28 min
  15. 15

    First-Order Resolution

    AdvancedComing soon

    Lifting resolution to FOL, factoring, and refutation proofs over quantified clause sets.

    Assumes: Unification

    30 min
  16. 16

    Forward and Backward Chaining

    IntermediateComing soon

    Generalised modus ponens, data- versus goal-driven inference, and Horn clause efficiency.

    Assumes: Unification

    26 min
  17. 17

    Soundness, Completeness and Compactness

    AdvancedComing soon

    What the metatheorems guarantee, Gödel's completeness theorem, compactness and the Löwenheim–Skolem theorem.

    Assumes: First-Order Resolution

    32 min
  18. 18

    Decidability and the Limits of Logic

    AdvancedComing soon

    Decidable versus semi-decidable, the halting problem, Church–Turing undecidability of FOL, and Gödel's incompleteness theorems.

    Assumes: Soundness, Completeness and Compactness

    34 min
  19. 19

    Second-Order Logic

    AdvancedComing soon

    Quantifying 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

    32 min
  20. 20

    Higher-Order Logic and Type Theory

    AdvancedComing soon

    Simple type theory, lambda abstraction, Church's formulation, and HOL in interactive theorem provers.

    Assumes: Second-Order Logic

    30 min
  21. 21

    Modal Logic

    AdvancedComing soon

    Necessity and possibility, Kripke frames and accessibility relations, and the K, T, S4 and S5 systems.

    Assumes: First-Order Logic: Semantics

    32 min
  22. 22

    Temporal Logic and Model Checking

    AdvancedComing soon

    LTL and CTL operators, expressing safety and liveness, and model checking as verification.

    Assumes: Modal Logic

    30 min
  23. 23

    Epistemic and Doxastic Logic

    AdvancedComing soon

    Reasoning about knowledge and belief, common knowledge, and multi-agent puzzles.

    Assumes: Modal Logic

    26 min
  24. 24

    Description Logics and OWL

    AdvancedComing soon

    Concepts, roles and individuals; the ALC family, TBox and ABox, and the reasoning tasks behind OWL ontologies.

    Assumes: First-Order Logic: Semantics

    32 min
  25. 25

    Horn Clauses and Logic Programming

    AdvancedComing soon

    Definite clauses, SLD resolution, Prolog execution order, negation as failure, and Datalog for queries.

    Assumes: Forward and Backward Chaining

    32 min
  26. 26

    Non-Monotonic Reasoning

    AdvancedComing soon

    Why classical entailment cannot retract conclusions; default logic, the closed-world assumption, circumscription and answer set programming.

    Assumes: Horn Clauses and Logic Programming

    30 min
  27. 27

    Many-Valued and Fuzzy Logic

    AdvancedComing soon

    Three-valued and Łukasiewicz systems, fuzzy sets and membership functions, t-norms, and fuzzy inference worked end to end.

    Assumes: Propositional Logic

    32 min
  28. 28

    Intuitionistic and Constructive Logic

    AdvancedComing soon

    Rejecting excluded middle, the BHK interpretation, and the Curry–Howard correspondence between proofs and programs.

    Assumes: Natural Deduction

    30 min
  29. 29

    Probabilistic Logic

    AdvancedComing soon

    Attaching probabilities to formulas, Markov logic networks, probabilistic soft logic, and the link to graphical models.

    Assumes: First-Order Resolution · Bayes' Theorem

    30 min
  30. 30

    Logic Meets Machine Learning

    AdvancedComing soon

    Neuro-symbolic architectures, differentiable logic and fuzzy relaxations, inductive logic programming, and using solvers to verify model behaviour.

    Assumes: Probabilistic Logic · SAT and SMT Solvers

    30 min