Combining Texts

All the ideas for 'Higher-Order Logic', 'Sentences' and 'Particle Physics'

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27 ideas

4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX
The axiom of choice is controversial, but it could be replaced [Shapiro]
5. Theory of Logic / A. Overview of Logic / 3. Value of Logic
Logicians acknowledge too few things, while others acknowledge too many [Fitzralph]
5. Theory of Logic / A. Overview of Logic / 5. First-Order Logic
First-order logic is Complete, and Compact, with the Löwenheim-Skolem Theorems [Shapiro]
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
Some say that second-order logic is mathematics, not logic [Shapiro]
If the aim of logic is to codify inferences, second-order logic is useless [Shapiro]
5. Theory of Logic / B. Logical Consequence / 1. Logical Consequence
Logical consequence can be defined in terms of the logical terminology [Shapiro]
5. Theory of Logic / G. Quantification / 5. Second-Order Quantification
Second-order variables also range over properties, sets, relations or functions [Shapiro]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
Up Löwenheim-Skolem: if natural numbers satisfy wffs, then an infinite domain satisfies them [Shapiro]
The Löwenheim-Skolem Theorems fail for second-order languages with standard semantics [Shapiro]
The Löwenheim-Skolem theorem seems to be a defect of first-order logic [Shapiro]
Downward Löwenheim-Skolem: if there's an infinite model, there is a countable model [Shapiro]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / e. Peano arithmetic 2nd-order
Second-order logic has the expressive power for mathematics, but an unworkable model theory [Shapiro]
8. Modes of Existence / B. Properties / 11. Properties as Sets
Logicians use 'property' and 'set' interchangeably, with little hanging on it [Shapiro]
27. Natural Reality / A. Classical Physics / 1. Mechanics / c. Forces
The strong force has a considerably greater range than the weak force [Martin,BR]
27. Natural Reality / A. Classical Physics / 2. Thermodynamics / c. Conservation of energy
If an expected reaction does not occur, that implies a conservation law [Martin,BR]
27. Natural Reality / B. Modern Physics / 2. Electrodynamics / a. Electrodynamics
Electron emit and reabsorb photons, which create and reabsorb virtual electrons and positrons [Martin,BR]
27. Natural Reality / B. Modern Physics / 2. Electrodynamics / b. Fields
A 'field' is just a region to which points can be assigned in space and time [Martin,BR]
The Higgs field, unlike others, has a nozero value in a state without particles [Martin,BR]
27. Natural Reality / B. Modern Physics / 2. Electrodynamics / c. Electrons
Many physicists believe particles have further structure, if only we could see it [Martin,BR]
27. Natural Reality / B. Modern Physics / 2. Electrodynamics / d. Quantum mechanics
Uncertainty allows very brief violations of energy conservation - even shorter with higher energies [Martin,BR]
The Exclusion Principle says no two fermions occupy the same state, with the same numbers [Martin,BR]
27. Natural Reality / B. Modern Physics / 4. Standard Model / b. Standard model
The standard model combines theories of strong interaction, and electromagnetic and weak interaction [Martin,BR]
27. Natural Reality / B. Modern Physics / 4. Standard Model / c. Particle properties
Eletrons don't literally 'spin', because they are point-like [Martin,BR]
Virtual particles surround any charged particle [Martin,BR]
The properties of a particle are determined by its quantum numbers and its mass [Martin,BR]
27. Natural Reality / B. Modern Physics / 5. Unified Models / b. String theory
String theory only has one free parameter (tension) - unlike the standard model with 19 [Martin,BR]
27. Natural Reality / F. Chemistry / 2. Modern Elements
An 'element' is what cannot be decomposed by chemistry [Martin,BR]