Chapter 15: Universe Ontology—From Phenomena to Mathematical Definition

“Before we define ‘what universe is’, we cannot even begin to discuss its properties. This chapter will give complete mathematical definition of universe—a terminal object of tenfold structure.”

Introduction: What is “Universe”?

In previous 14 chapters, we have established core framework of GLS unified theory:

• Chapters 1-3: Mathematical foundations and axioms
• Chapter 4: IGVP—Deriving gravity from entropy
• Chapter 5: Unified Time Scale—Unification of three times
• Chapter 6: Boundary Time Geometry—Boundary origin of physical reality
• Chapter 7: Causal Structure—Unification of causality-time-entropy
• Chapter 8: Topological Constraints—Z₂ holonomy and fermions
• Chapter 9: QCA Universe—Quantum cellular automaton
• Chapter 10: Matrix Universe—Observer and mind-universe isomorphism
• Chapter 11: Final Unification—Consistency functional $\delta I[\mathfrak{U}]=0$
• Chapter 12: Applications and Tests—Black holes, gravitational waves, cosmology
• Chapter 13: Advanced Topics—Quantum chaos, time crystals, consciousness
• Chapter 14: Learning Path and Overview

But there is a fundamental question we have left unresolved:

What exactly is “universe”?

This is not a philosophical question, but a mathematical question. If we don’t even have strict definition of “universe” itself, then all properties we discussed in previous chapters—time scale, causal structure, observer—lack solid foundation.

Three Levels of Confusion

In traditional physics, understanding of “universe” has three levels of confusion:

1. Phenomenological Level: Universe is “Everything We See”

This is most naive definition: Universe is sum of all stars, galaxies, matter, energy.

Problems:

• “Seeing” depends on observer, different observers may see different “everything”
• This is only collection of phenomena, not ontological definition
• Doesn’t tell us “why these things form a whole”

Analogy: Like saying “forest is all trees we see”, but doesn’t explain why these trees form a forest rather than random tree collection.

2. Physics Level: Universe is “Spacetime + Matter Fields”

In general relativity, universe is a Lorentz manifold $(M,g)$ plus energy-momentum tensor $T_{ab}$ satisfying Einstein equation.

Problems:

• Only geometry, no quantum
• Only evolution, no observer
• Only spacetime, no causality, entropy, information

Analogy: Like saying “music is notes on score”, ignoring performance, audience, emotional experience.

3. Quantum Field Theory Level: Universe is “Operator Algebra + State”

In quantum field theory, universe is operator algebra $\mathcal{A}$ on Hilbert space $\mathcal{H}$ plus a state $\omega$.

Problems:

• Only quantum, no geometry
• Only algebra, no time
• Only state, no dynamics

Analogy: Like saying “painting is arrangement of pigments”, ignoring canvas, perspective, viewer’s perspective.

Goal of This Chapter: Unified Ontology

This chapter will give unified mathematical definition of universe, simultaneously containing:

1. Events and Causality $U_{\text{evt}}$: What “happens” in universe
2. Geometry and Spacetime $U_{\text{geo}}$: Where things “happen”
3. Measure and Probability $U_{\text{meas}}$: How universe “is observed”
4. Quantum Field Theory $U_{\text{QFT}}$: “Quantum structure” of universe
5. Scattering and Spectrum $U_{\text{scat}}$: “Dynamics” of universe
6. Modular Flow and Thermal $U_{\text{mod}}$: “Thermodynamics” of universe
7. Generalized Entropy $U_{\text{ent}}$: “Information” of universe
8. Observer Network $U_{\text{obs}}$: “Perspectives” in universe
9. Categorical Structure $U_{\text{cat}}$: “Logic” of universe
10. Computational Realizability $U_{\text{comp}}$: “Computability” of universe

These ten aspects are not independent, but projections of same ontology in different categories. We will prove:

Core Theorem (Universe Uniqueness): $$\mathfrak{U}=(U_{\text{evt}},U_{\text{geo}},U_{\text{meas}},U_{\text{QFT}},U_{\text{scat}},U_{\text{mod}},U_{\text{ent}},U_{\text{obs}},U_{\text{cat}},U_{\text{comp}})$$

Uniquely determined up to isomorphism. That is: There is only one universe (up to isomorphism) satisfying all consistency conditions.

Why Tenfold Structure?

You might ask: Why ten components? Why not three or twenty?

Answer: This is minimal requirement for completeness.

Intuitive Understanding: Ten Perspectives on Same World

Imagine you want to completely describe a city, you need:

1. Map (Geometry) - Where streets are
2. Event Schedule (Causality) - When what happens
3. Population Distribution (Measure) - Where people are
4. Power Grid (Field Theory) - How energy flows
5. Traffic Flow (Scattering) - How vehicles traverse
6. Temperature Field (Modular Flow) - How heat distributes
7. Information Network (Entropy) - How data propagates
8. Surveillance Network (Observer) - Who watches what
9. Planning Diagram (Category) - How whole is organized
10. Simulator (Computation) - How to reconstruct with finite data

Missing any perspective, you cannot completely understand this city. Similarly, missing any component of tenfold structure, you cannot completely define universe.

Mathematical Understanding: Terminal Object in Category Theory

In category theory, we define a category $\mathbf{Univ}$:

• Objects: All candidate “universe structures”
• Morphisms: Structure-preserving isomorphisms

Terminal object $\mathfrak{U}$ satisfies: For any object $V$, exists unique morphism $V\to \mathfrak{U}$.

In other words: All candidate universes “map to” unique real universe.

graph TB
    V1["Candidate Universe V1"]
    V2["Candidate Universe V2"]
    V3["Candidate Universe V3"]
    U["Real Universe 𝔘 (Terminal Object)"]

    V1 -->|"Unique Morphism"| U
    V2 -->|"Unique Morphism"| U
    V3 -->|"Unique Morphism"| U

    style U fill:#f9f,stroke:#333,stroke-width:4px
    style V1 fill:#bbf,stroke:#333,stroke-width:2px
    style V2 fill:#bbf,stroke:#333,stroke-width:2px
    style V3 fill:#bbf,stroke:#333,stroke-width:2px

Overview of Tenfold Structure

Let us first overview ten components and their interrelationships:

First Layer: Foundation Layer

1. Events and Causality $U_{\text{evt}}$ (Article 01)

Definition: $$U_{\text{evt}}=(X,⪯,\mathcal{C})$$

• $X$: Set of events
• $⪯$: Causal partial order (who influences whom)
• $\mathcal{C}$: Family of causal fragments (local causal networks)

Intuition: Universe is first collection of “things that happen”, some things can influence others (causal relations).

Analogy: Like dominoes, each domino is an event, $p⪯q$ means “$p$ falling causes $q$ to fall”.

2. Geometry and Spacetime $U_{\text{geo}}$ (Article 01)

Definition: $$U_{\text{geo}}=(M,g,{\Phi }_{\text{evt}},{\Phi }_{\text{cau}})$$

• $M$: Four-dimensional smooth manifold
• $g$: Lorentz metric (signature $-+++$)
• ${\Phi }_{\text{evt}}$: Embedding of events into spacetime
• ${\Phi }_{\text{cau}}$: Alignment of causal partial order with light cone structure

Intuition: Events not only “happen”, but happen at “some spacetime location”.

Analogy: Dominoes not floating in void, but placed on curved tabletop (curved spacetime).

3. Measure and Probability $U_{\text{meas}}$ (Article 02)

Definition: $$U_{\text{meas}}=(\Omega ,\mathcal{F},\mathbb{P},\Psi )$$

• $(\Omega ,\mathcal{F},\mathbb{P})$: Complete probability space
• $\Psi :\Omega \to X$: Random event mapping

Intuition: We are not omniscient, what we observe are “samples”, need probability description.

Analogy: You cannot see all dominoes simultaneously, can only sample observe, use statistics to infer global.

Second Layer: Quantum and Dynamics Layer

4. Quantum Field Theory $U_{\text{QFT}}$ (Article 03)

Definition: $$U_{\text{QFT}}=(\mathcal{O}(M),\mathcal{A},\omega )$$

• $\mathcal{O}(M)$: Family of spacetime open sets
• $\mathcal{A}:\mathcal{O}(M)\to C^{\ast }\text{-Alg}$: Local operator algebra net (Haag-Kastler axioms)
• $\omega$: State

Intuition: Physics not classical particles, but quantum fields—each spacetime region has operator algebra.

Analogy: Dominoes not rigid objects, but “quantum domino cloud”, each position is superposition of probability amplitudes.

5. Scattering and Spectrum $U_{\text{scat}}$ (Article 03)

Definition: $$U_{\text{scat}}=((H,H_0),S(\omega ),Q(\omega ),\kappa (\omega ))$$

• $(H,H_0)$: Scattering pair (self-adjoint operators)
• $S(\omega )$: Scattering matrix
• $Q(\omega )$: Wigner-Smith group delay matrix
• $\kappa (\omega )$: Unified time scale density

Key Formula (Unified Time Scale Master Formula): $$\kappa (\omega )=\frac{{\phi }^{\prime }(\omega )}{\pi }={\rho }_{\text{rel}}(\omega )=\frac{1}{2\pi }\text{tr}Q(\omega )$$

Intuition: Dynamics of universe described by scattering processes, time scale uniformly given by scattering phase, density of states, group delay.

Analogy: Dominoes falling not instantaneous, but “wave propagation”, scattering matrix describes how waves propagate from one end to another.

6. Modular Flow and Thermal Time $U_{\text{mod}}$ (Article 03)

Definition: $$U_{\text{mod}}=(S,J,\Delta ,{\sigma }_t^{\omega },K_{\omega })$$

• $S$: Modular operator
• $J$: Modular conjugation
• $\Delta$: Modular Hamiltonian
• ${\sigma }_t^{\omega }$: Modular flow (Tomita-Takesaki theory)
• $K_{\omega }=-\log \Delta$: Modular Hamiltonian operator

Intuition: Quantum states have “intrinsic time”—modular flow, unified with thermodynamic time, geometric time, scattering time.

Analogy: Each domino carries its own “internal clock” (modular flow), all clocks synchronized under unified scale.

Third Layer: Information and Observer Layer

7. Generalized Entropy and Gravity $U_{\text{ent}}$ (Article 04)

Definition: $$U_{\text{ent}}=(\mathcal{D},S_{\text{gen}},\text{QNEC},\text{QFC})$$

• $\mathcal{D}$: Family of small causal diamonds
• $S_{\text{gen}}(\Sigma )=\frac{A(\Sigma )}{4G\hslash }+S_{\text{out}}(\Sigma )$: Generalized entropy
• QNEC: Quantum Null Energy Condition
• QFC: Quantum Focussing Conjecture

Core Principle (IGVP): $$\delta S_{\text{gen}}=0\iff G_{ab}+\Lambda g_{ab}=8\pi G⟨T_{ab}⟩$$

Intuition: Gravitational field equation not independent law, but geometric manifestation of generalized entropy extremum.

Analogy: Soap bubble automatically forms sphere (minimum surface area), spacetime automatically satisfies Einstein equation (generalized entropy extremum).

8. Observer Network $U_{\text{obs}}$ (Article 04)

Definition: $$U_{\text{obs}}=(\mathcal{O},\text{worldline},\text{res},\text{model},\text{update})$$

Each observer: $$O_i=({\gamma }_i,{\Lambda }_i,{\mathcal{A}}_i,{\omega }_i,{\mathcal{M}}_i,U_i)$$

• ${\gamma }_i$: Worldline
• ${\Lambda }_i$: Resolution scale
• ${\mathcal{A}}_i$: Observable algebra
• ${\omega }_i$: Local state
• ${\mathcal{M}}_i$: Candidate model family
• $U_i$: Update rule

Intuition: Universe has “perspectives”—observers observe along worldlines, have finite resolution, maintain internal models.

Analogy: Multiple cameras photograph dominoes from different angles, each camera can only see part, reconstruct global through information fusion.

Fourth Layer: Logic and Computation Layer

9. Category and Topology $U_{\text{cat}}$ (Article 05)

Definition: $$U_{\text{cat}}=(\mathbf{Univ},\mathfrak{U},\Pi )$$

• $\mathbf{Univ}$: 2-category of universe candidate structures
• $\mathfrak{U}$: Terminal object
• $\Pi$: Projection cone (inverse limit)

Core Property: $$\mathfrak{U}\simeq \underleftarrow{\lim }(U_{\text{geo}},U_{\text{QFT}},U_{\text{scat}},U_{\text{mod}},U_{\text{ent}},U_{\text{obs}},\dots )$$

Intuition: Universe is “common core” of all component structures—inverse limit.

Analogy: Multiple map projections (Mercator, Robinson, etc.) all project from same Earth, Earth is “inverse limit” of all projections.

10. Computation and Realizability $U_{\text{comp}}$ (Article 05)

Definition: $$U_{\text{comp}}=({\mathcal{M}}_{\text{TM}},\text{Enc},\text{Sim})$$

• ${\mathcal{M}}_{\text{TM}}$: Turing machine space
• $\text{Enc}:\mathbf{Univ}\to {\mathcal{M}}_{\text{TM}}$: Encoding functor
• $\text{Sim}:{\mathcal{M}}_{\text{TM}}\rightrightarrows \mathbf{Univ}$: Simulation functor

Intuition: Universe though possibly uncomputable, can be “upper-bound encoded” by finite information.

Analogy: Though you cannot precisely simulate entire city, can give good approximation with finite parameters (population, number of roads, traffic flow).

Interrelationships of Tenfold Structure

These ten components are not independent puzzle pieces, but highly coupled:

graph TB
    subgraph "Logic Layer"
        U_cat["U_cat Categorical Structure<br/>(Terminal Object)"]
        U_comp["U_comp Computational Realizability<br/>(Encoding/Simulation)"]
    end

    subgraph "Information Layer"
        U_ent["U_ent Generalized Entropy<br/>(IGVP)"]
        U_obs["U_obs Observer Network<br/>(Multiple Perspectives)"]
    end

    subgraph "Dynamics Layer"
        U_QFT["U_QFT Quantum Field Theory<br/>(Operator Algebra)"]
        U_scat["U_scat Scattering Spectrum<br/>(Unified Scale)"]
        U_mod["U_mod Modular Flow<br/>(Thermal Time)"]
    end

    subgraph "Foundation Layer"
        U_evt["U_evt Event Causality<br/>(Partial Order)"]
        U_geo["U_geo Spacetime Geometry<br/>(Metric)"]
        U_meas["U_meas Measure Probability<br/>(Statistics)"]
    end

    U_cat -->|"Inverse Limit"| U_ent
    U_cat -->|"Inverse Limit"| U_obs
    U_comp -->|"Upper Bound"| U_QFT

    U_ent -->|"Extremum Condition"| U_geo
    U_obs -->|"Worldline"| U_geo
    U_obs -->|"Local State"| U_QFT

    U_QFT -->|"GNS Construction"| U_mod
    U_scat -->|"Scale Alignment"| U_mod
    U_scat -->|"Time Function"| U_geo

    U_geo -->|"Light Cone"| U_evt
    U_meas -->|"Random Events"| U_evt
    U_mod -->|"Thermal Time"| U_evt

    style U_cat fill:#f9f,stroke:#333,stroke-width:3px
    style U_comp fill:#f9f,stroke:#333,stroke-width:3px
    style U_ent fill:#9f9,stroke:#333,stroke-width:2px
    style U_obs fill:#9f9,stroke:#333,stroke-width:2px
    style U_QFT fill:#99f,stroke:#333,stroke-width:2px
    style U_scat fill:#99f,stroke:#333,stroke-width:2px
    style U_mod fill:#99f,stroke:#333,stroke-width:2px
    style U_evt fill:#ff9,stroke:#333,stroke-width:2px
    style U_geo fill:#ff9,stroke:#333,stroke-width:2px
    style U_meas fill:#ff9,stroke:#333,stroke-width:2px

Key Constraint Relations

Core Insight: These constraints are overdetermined—satisfying some constraints automatically satisfies others. This is why universe is unique up to isomorphism.

Unified Time Scale: Red Thread Penetrating Ten Layers

In tenfold structure, there is a red thread running throughout—unified time scale $[\tau ]$:

$$[\tau ]=\{T_{\text{cau}},T_{\text{geo}},{\tau }_{\text{scatt}},t_{\text{mod}},{\tau }_{\text{geom}},{\tau }_i{\}}_{\text{affine equivalent}}$$

That is:

• $T_{\text{cau}}$: Causal time ($U_{\text{evt}}$)
• $T_{\text{geo}}$: Geometric time ($U_{\text{geo}}$)
• ${\tau }_{\text{scatt}}$: Scattering time ($U_{\text{scat}}$)
• $t_{\text{mod}}$: Modular time ($U_{\text{mod}}$)
• ${\tau }_{\text{geom}}$: Boundary geometric time ($U_{\text{ent}}$)
• ${\tau }_i$: Observer proper time ($U_{\text{obs}}$)

All belong to same equivalence class, differing only by affine transformation ${\tau }^{\prime }=a\tau +b$ ($a>0$).

Intuitive Understanding: Synchronizing Six “Clocks”

Imagine you have six different brands of watches:

1. Causal Clock: Orders events by sequence (domino falling order)
2. Geometric Clock: Measures by spacetime metric (distance light travels)
3. Scattering Clock: Based on wave phase accumulation (scattering phase/π)
4. Modular Clock: Based on quantum state modular flow (thermal time)
5. Gravitational Clock: Based on boundary Brown-York energy (geometric Hamiltonian)
6. Subjective Clock: Proper time along your worldline

GLS theory tells you: These six clocks, though appearing different, always have linear relationship in readings—they are “synchronized”.

Mathematical Formalization: Scale Equivalence Class

Define equivalence relation $\sim$:

$${\tau }_1\sim {\tau }_2\iff \exists a>0,b\in \mathbb{R}:{\tau }_2=a{\tau }_1+b$$

Then unified time scale equivalence class is:

$$[\tau ]:=\{{\tau }^{\prime }\mid {\tau }^{\prime }\sim \tau \}$$

Physical Meaning: Absolute starting point ($b$) and unit ($a$) of time are arbitrary, but relative rate of passage is fixed, given by $\kappa (\omega )$.

Terminal Object Property of Universe

In category $\mathbf{Univ}$, universe $\mathfrak{U}$ not only exists, but is terminal object:

Definition: Terminal Object

An object $\mathfrak{U}$ is terminal object if:

$$\forall V\in \text{Ob}(\mathbf{Univ}),\exists !\varphi :V\to \mathfrak{U}$$

That is: From any candidate universe $V$ to real universe $\mathfrak{U}$, there exists unique structure-preserving morphism $\varphi$.

Intuitive Understanding: All Paths Lead to Unique Truth

Imagine you are in a maze:

• Each room is a “candidate universe” $V$
• Each passage is a “structure-preserving map”
• Center of maze is “real universe” $\mathfrak{U}$

Terminal object property says: No matter which room you start from, there is always unique optimal path to center.

graph TB
    V1["Candidate Universe V1<br/>Classical Mechanics"]
    V2["Candidate Universe V2<br/>Quantum Mechanics"]
    V3["Candidate Universe V3<br/>General Relativity"]
    V4["Candidate Universe V4<br/>QFT"]
    U["Real Universe 𝔘<br/>(Tenfold Structure Terminal Object)"]

    V1 -->|"Continuous Limit"| U
    V2 -->|"GNS Construction"| U
    V3 -->|"IGVP"| U
    V4 -->|"Scattering-Scale Alignment"| U

    style U fill:#f9f,stroke:#333,stroke-width:4px
    style V1 fill:#bbf,stroke:#333,stroke-width:1px
    style V2 fill:#bbf,stroke:#333,stroke-width:1px
    style V3 fill:#bbf,stroke:#333,stroke-width:1px
    style V4 fill:#bbf,stroke:#333,stroke-width:1px

Mathematical Meaning: Uniqueness Theorem

Theorem (Universe Uniqueness): Let ${\mathfrak{U}}_1,{\mathfrak{U}}_2$ both be universe objects satisfying all consistency conditions of tenfold structure, then

$${\mathfrak{U}}_1\cong {\mathfrak{U}}_2$$

isomorphic in category $\mathbf{Univ}$.

Proof Strategy:

1. By terminal object property, exist unique morphisms ${\varphi }_1:{\mathfrak{U}}_1\to {\mathfrak{U}}_2$ and ${\varphi }_2:{\mathfrak{U}}_2\to {\mathfrak{U}}_1$
2. By uniqueness, ${\varphi }_2\circ {\varphi }_1={\text{id}}_{{\mathfrak{U}}_1}$ and ${\varphi }_1\circ {\varphi }_2={\text{id}}_{{\mathfrak{U}}_2}$
3. Therefore ${\varphi }_1$ is isomorphism

Philosophical Meaning: Universe is not “constructed”, but mathematical object uniquely existing under consistency constraints.

Chapter Structure and Learning Path

This chapter consists of 10 articles (including this introduction), gradually establishing tenfold structure:

Learning Path Diagram

graph LR
    A["00. Introduction<br/>(This Article)"]
    B["01. Event-Geometry-Measure<br/>Three Components"]
    C["02. QFT-Scattering-Modular<br/>Three Components"]
    D["03. Entropy-Observer-Category<br/>Three Components"]
    E["04. Computation-Completeness"]
    F["05. Compatibility Conditions"]
    G["06. Uniqueness Theorem"]
    H["07. Observer-Free<br/>Ontologization"]
    I["08. Summary"]

    A --> B
    A --> C
    A --> D
    B --> E
    C --> E
    D --> E
    E --> F
    F --> G
    G --> H
    H --> I

    style A fill:#f9f,stroke:#333,stroke-width:2px
    style I fill:#9f9,stroke:#333,stroke-width:2px

Article List

Reading Suggestions

Quick Path (Understand main ideas):

• 00 Introduction → 01 Tenfold Structure Definition → 06 Compatibility → 09 Summary

Standard Path (Complete learning):

• Read all 00-09 in order

Deep Research (Mathematical details):

• Especially focus on 03 (scattering-modular alignment), 05 (computational complexity), 07 (uniqueness proof), 08 (observer-free limit)

Key Insight: Universe is Not “Collection of Everything”

Before entering subsequent articles, remember core insight of this chapter:

Universe is not simple collection of “all things”, but unique mathematical structure satisfying overdetermined consistency conditions.

Comparison: Traditional View vs GLS Ontology

Analogy: Universe = Unique Solution of Sudoku

Imagine a super complex Sudoku game:

• Cells: Various components of tenfold structure
• Rules: Compatibility conditions
• Given Numbers: Observed physical constants

GLS theory says: This Sudoku has exactly one solution (up to symmetry)—that is our universe.

You cannot “arbitrarily fill” cells, because rules are overdetermined—once you fill a few key cells correctly, rest automatically determined.

Relations of This Chapter with Other Chapters

Relations with Previous Chapters

Relations with Subsequent Chapters

Philosophical Meaning: From Plurality to Unity

Ontological framework of this chapter solves an ancient philosophical problem: Relationship between one and many.

Classical Confusion

• Parmenides: Being is one, change is illusion
• Heraclitus: Everything flows, being is many
• Plato: Dualism between world of ideas (one) and world of phenomena (many)

GLS Solution

Tenfold structure tells us: One and many are different projections of same ontology.

$$\mathfrak{U}\simeq \underleftarrow{\lim }(U_{\text{evt}},U_{\text{geo}},\dots ,U_{\text{comp}})$$

• “One”: Inverse limit $\mathfrak{U}$ (ontology)
• “Many”: Various projections $U_i$ (phenomena)

They are not independently existing, but connected through projection cone $\Pi$.

Popular Analogy: Ten Sides of Elephant

Ancient Indian fable “Blind Men and Elephant”:

• One touching leg says “elephant like pillar”
• One touching ear says “elephant like fan”
• One touching trunk says “elephant like snake”

Each is right, but incomplete. Tenfold structure is “complete elephant”—describing from ten sides simultaneously is real universe.

Preview: Next Article Content

In Article 01, we will give complete mathematical definition of tenfold structure:

$$\mathfrak{U}=(U_{\text{evt}},U_{\text{geo}},U_{\text{meas}},U_{\text{QFT}},U_{\text{scat}},U_{\text{mod}},U_{\text{ent}},U_{\text{obs}},U_{\text{cat}},U_{\text{comp}})$$

Including:

1. Precise mathematical definition of each component $U_i$
2. Morphisms and projections between them
3. Formalization of unified time scale equivalence class $[\tau ]$
4. Preliminary proof of terminal object property

Ready to dive into mathematical essence of universe!

Note: This article is Section 00 of Chapter 15 of GLS unified theory tutorial. Prerequisites see Chapters 1-14. Next section will enter strict mathematical definition of tenfold structure.

Key Terms English-Chinese Glossary:

• Ontology 本体论
• Terminal Object 终对象
• Inverse Limit 逆极限
• Category Equivalence 范畴等价
• Consistency Condition 一致性条件
• Overdetermined 过度决定