Collecting Things Together: Sets / 1: |
The Intuitive Concept of a Set / 1.1: |
Basic Relations between Sets / 1.2: |
Inclusion / 1.2.1: |
Identity / 1.2.2: |
Proper Inclusion / 1.2.3: |
Euler Diagrams / 1.2.4: |
Venn Diagrams / 1.2.5: |
Ways of Defining a Set / 1.2.6: |
The Empty Set / 1.3: |
Emptiness / 1.3.1: |
Disjoint Sets / 1.3.2: |
Boolean Operations on Sets / 1.4: |
Intersection / 1.4.1: |
Union / 1.4.2: |
Difference and Complement / 1.4.3: |
Generalised Union and Intersection / 1.5: |
Power Sets / 1.6: |
Some Important Sets of Numbers / 1.7: |
Comparing Things: Relations / 2: |
Ordered Tuples, Cartesian Products, Relations / 2.1: |
Ordered Tuples / 2.1.1: |
Cartesian Products / 2.1.2: |
Relations / 2.1.3: |
Tables and Digraphs for Relations / 2.2: |
Tables for Relations / 2.2.1: |
Digraphs for Relations / 2.2.2: |
Operations on Relations / 2.3: |
Converse / 2.3.1: |
Join of Relations / 2.3.2: |
Composition of Relations / 2.3.3: |
Image / 2.3.4: |
Reflexivity and Transitivity / 2.4: |
Reflexivity / 2.4.1: |
Transitivity / 2.4.2: |
Equivalence Relations and Partitions / 2.5: |
Symmetry / 2.5.1: |
Equivalence Relations / 2.5.2: |
Partitions / 2.5.3: |
The Correspondence between Partitions and Equivalence Relations / 2.5.4: |
Relations for Ordering / 2.6: |
Partial Order / 2.6.1: |
Linear Orderings / 2.6.2: |
Strict Orderings / 2.6.3: |
Closing with Relations / 2.7: |
Transitive Closure of a Relation / 2.7.1: |
Closure of a Set under a Relation / 2.7.2: |
Associating One Item with Another: Functions / 3: |
What is a Function? / 3.1: |
Operations on Functions / 3.2: |
Domain and Range / 3.2.1: |
Image, Restriction, Closure / 3.2.2: |
Composition / 3.2.3: |
Inverse / 3.2.4: |
Injections, Surjections, Bijections / 3.3: |
Injectivity / 3.3.1: |
Surjectivity / 3.3.2: |
Bijective Functions / 3.3.3: |
Using Functions to Compare Size / 3.4: |
The Equinumerosity Principle / 3.4.1: |
The Principle of Comparison / 3.4.2: |
The Pigeonhole Principle / 3.4.3: |
Some Handy Functions / 3.5: |
Identity Functions / 3.5.1: |
Constant Functions / 3.5.2: |
Projection Functions / 3.5.3: |
Characteristic Functions / 3.5.4: |
Families of Sets / 3.5.5: |
Sequences / 3.5.6: |
Recycling Outputs as Inputs: Induction and Recursion / 4: |
What are Induction and Recursion? / 4.1: |
Proof by Simple Induction on the Positive Integers / 4.2: |
An Example / 4.2.1: |
The Principle behind the Example / 4.2.2: |
Definition by Simple Recursion on the Natural Numbers / 4.3: |
Evaluating Functions Defined by Recursion / 4.4: |
Cumulative Induction and Recursion / 4.5: |
Recursive Definitions Reaching Back more than One Unit / 4.5.1: |
Proof by Cumulative Induction / 4.5.2: |
Simultaneous Recursion and Induction / 4.5.3: |
Structural Recursion and Induction / 4.6: |
Defining Sets by Structural Recursion / 4.6.1: |
Proof by Structural Induction / 4.6.2: |
Defining Functions by Structural Recursion on their Domains / 4.6.3: |
Condition for Defining a Function by Structural Recursion / 4.6.4: |
When the Unique Decomposition Condition Fails? / 4.6.5: |
Recursion and Induction on Well-Founded Sets / 4.7: |
Well-Founded Sets / 4.7.1: |
The Principle of Proof by Well-Founded Induction / 4.7.2: |
Definition of a Function by Well-Founded Recursion on its Domain / 4.7.3: |
Recursive Programs / 4.8: |
Counting Things: Combinatorics / 5: |
Two Basic Principles: Addition and Multiplication / 5.1: |
Using the Two Basic Principles Together / 5.2: |
Four Ways of Selecting k Items out of n / 5.3: |
Counting Formulae: Permutations and Combinations / 5.4: |
The Formula for Permutations (O+R-) / 5.4.1: |
The Formula for Combinations (O-R-) / 5.4.2: |
Counting Formulae: Perms and Coms with Repetition / 5.5: |
The Formula for Permutations with Repetition Allowed (O+R+) / 5.5.1: |
The Formula for Combinations with Repetition Allowed (O-R+) / 5.5.2: |
Rearrangements and Partitions / 5.6: |
Rearrangements / 5.6.1: |
Counting Partitions with a Given Numerical Configuration / 5.6.2: |
Weighing the Odds: Probability / 6: |
Finite Probability Spaces / 6.1: |
Basic Definitions / 6.1.1: |
Properties of Probability Functions / 6.1.2: |
Philosophy and Applications / 6.2: |
Some Simple Problems / 6.3: |
Conditional Probability / 6.4: |
Interlude: Simpson's Paradox / 6.5: |
Independence / 6.6: |
Bayes' Theorem / 6.7: |
Random Variables and Expected Values / 6.8: |
Random Variables / 6.8.1: |
Expectation / 6.8.2: |
Induced Probability Distributions / 6.8.3: |
Expectation Expressed using Induced Probability Functions / 6.8.4: |
Squirrel Math: Trees / 7: |
My First Tree / 7.1: |
Rooted Trees / 7.2: |
Labelled Trees / 7.3: |
Interlude: Parenthesis-Free Notation / 7.4: |
Binary Search Trees / 7.5: |
Unrooted Trees / 7.6: |
Definition of Unrooted Tree / 7.6.1: |
Properties of Unrooted Trees / 7.6.2: |
Finding Spanning Trees / 7.6.3: |
Yea and Nay: Propositional Logic / 8: |
What is Logic? / 8.1: |
Structural Features of Consequence / 8.2: |
Truth-Functional Connectives / 8.3: |
Tautologicality / 8.4: |
The Language of Propositional Logic / 8.4.1: |
Assignments and Valuations / 8.4.2: |
Tautological Implication / 8.4.3: |
Tautological Equivalence / 8.4.4: |
Tautologies and Contradictions / 8.4.5: |
Normal Forms, Least letter-Sets, Greatest Modularity / 8.5: |
Disjunctive Normal Form / 8.5.1: |
Conjunctive Normal Form / 8.5.2: |
Eliminating Redundant Letters / 8.5.3: |
Most Modular Representation / 8.5.4: |
Semantic Decomposition Trees / 8.6: |
Natural Deduction / 8.7: |
Enchainment / 8.7.1: |
Second-Level (alias Indirect) Inference / 8.7.2: |
Something about Everything: Quantificational Logic / 9: |
The Language of Quantifiers / 9.1: |
Some Examples / 9.1.1: |
Systematic Presentation of the Language / 9.1.2: |
Freedom and Bondage / 9.1.3: |
Some Basic Logical Equivalences / 9.2: |
Semantics for Quantificational Logic / 9.3: |
Interpretations / 9.3.1: |
Valuating Terms under an Interpretation / 9.3.2: |
Valuating Formulae under an Interpretation: Basis / 9.3.3: |
Valuating Formulae under an Interpretation: Recursion Step / 9.3.4: |
The x-Variant Reading of the Quantifiers / 9.3.5: |
The Substitutional Reading of the Quantifiers / 9.3.6: |
Logical Consequence etc / 9.4: |
Natural Deduction with Quantifiers / 9.5: |
Index |
Collecting Things Together: Sets / 1: |
The Intuitive Concept of a Set / 1.1: |
Basic Relations between Sets / 1.2: |
Inclusion / 1.2.1: |
Identity / 1.2.2: |
Proper Inclusion / 1.2.3: |