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* Update Peihong_Xie_Project_2_50375781.md

fix typo

* Update Peihong_Xie_Project_2_50375781.md

I'm unsure to how to infer a conclusion about D(a, e) and D(a, g)

* Update Peihong_Xie_Project_2_50375781.md

fix typo
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Expand Up @@ -36,7 +36,7 @@ Answer:

K = (T,A) such that

T={$PP ≡ P\sqcap ¬P^-$,
T={PP ≡ P ⊔ ¬P<sup>-</sup>,

$iPP ≡ P^-\sqcap ¬P$,

Expand Down Expand Up @@ -113,7 +113,7 @@ class Mary

Answer:

(a) ∃R.(∀R. $\top$) $\sqcap$ ∀R.$\top$
(a) $∃R.(∀R.\top)\sqcap ∀R.\top$

(b) $∃R.T \sqcap ∃R^-.(∃R.T)$

Expand Down Expand Up @@ -156,7 +156,7 @@ D((d2)) -->|parentOf|M((m2))
D((d2)) -->|parentOf|N((n2))
```

It is clear that $p$ = {(a1,a2),(b1,b2),(b1,c2),(b1,d2),(c1,e2),(c1,f2),(c1,g2),(c1,h2),(c1,m2),(c1,n2)} is a bisimulation between $I_1$ and $I_2$, so we have ($I_1$, a1)~($I_2$, a2). However, a2$\in$($\ge3 parentOf.(\ge2 parentOf)$)<sup>I<sub>2<sub></sup>, but a1$\notin$($\ge3 parentOf.(\ge2 parentOf)$)<sup>I<sub>1<sub></sup>, so ($\ge3 parentOf.(\ge2 parentOf)$) is not a ALC concept (otherwise it should be the case that a1$\in$($\ge3 parentOf.(\ge2 parentOf)$)<sup>I<sub>1<sub></sup>). Therefore, we find that a ALCN concept which is not ALC concept, showing that ALCN is more expressive than ALC.
It is clear that $p$ = {(a1,a2),(b1,b2),(b1,c2),(b1,d2),(c1,e2),(c1,f2),(c1,g2),(c1,h2),(c1,m2),(c1,n2)} is a bisimulation between $I_1$ and $I_2$, so we have ($I_1$, a1)~($I_2$, a2). However, $a2\in(\ge3 parentOf.(\ge2 parentOf))$<sup>I<sub>2<sub></sup>, but $a1\notin(\ge3 parentOf.(\ge2 parentOf))$<sup>I<sub>1<sub></sup>, so $(\ge3 parentOf.(\ge2 parentOf))$ is not a ALC concept (otherwise it should be the case that $a1\in(\ge3 parentOf.(\ge2 parentOf))$<sup>I<sub>1<sub></sup>). Therefore, we find that a ALCN concept which is not ALC concept, showing that ALCN is more expressive than ALC.

**[5]** Provide an interpretation I<sub>1</sub> for ALC and an interpretation I<sub>2</sub> for ALCN - each distinct from any interpretation covered in class so far - and construct a bisimulation that _does not_ demonstrate ALCN is more expressive than ALC. Use the [mermaid syntax](https://github.com/mermaid-js/mermaid) of markdown to provide a graphical representation of your work. Feel free to use the [mermaid live editor](https://mermaid.live/) when diagramming.

Expand Down Expand Up @@ -219,9 +219,9 @@ Answer:

Answer:

(1) When we say that a concept like "Dog" is satisfiable in a description logic, we mean that there is a model to assign some individual dogs to it. Now every satisfiable concept in that description logic has a finite model, a model which has only finitely many elements, then we say that logic has _finite model property_.
(1) When we say that a concept like "Dog" is satisfiable in a description logic, we mean that there is a model to assign some individual dogs to it. Now if every satisfiable concept in that description logic has a finite model, a model which has only finitely many elements, then we say that logic has _finite model property_.

(2) Example: Consider a simple _ALC_ T-box T<sup>1</sup>={$Dog \sqsubseteq Mammal$, $Person \equiv Rational \sqcap Mammal$}. The _ALC_ concept $Spider$ is satisfiable with respect to T<sup>1</sup>, and it is not difficult to find that $Spider$ has a finite model with respect to T<sup>1</sup>. For example, $I_1=(\bigtriangleup^1,.^1)$ such that:
(2) Example: Consider a simple _ALC_ T-box T<sup>1</sup>={$Dog\sqsubseteq Mammal$, $Person\equiv Rational\sqcap Mammal$}. The _ALC_ concept $Spider$ is satisfiable with respect to T<sup>1</sup>, and it is not difficult to find that $Spider$ has a finite model with respect to T<sup>1</sup>. For example, $I_1=(\bigtriangleup^1,.^1)$ such that:

$\bigtriangleup^1$={a,b,c,d}

Expand All @@ -243,9 +243,9 @@ It is clear that $I_1$ is a model of T<sup>1</sup>, and $Spider$ has an instance

Answer:

(1) When we say that a concept like "Father" is satisfiable in a description logic, we mean that there is a model to assign some individual men to it. Now every satisfiable concept in that description logic has a tree model, then we say that logic has _tree model property_. Here a model is a _tree model_ if it can be represented as a tree-like graph, which has only one root, viz. a node without parent, and every child node has only one parent.
(1) When we say that a concept like "Father" is satisfiable in a description logic, we mean that there is a model to assign some individual men to it. Now if every satisfiable concept in that description logic has a tree model, then we say that logic has _tree model property_. Here a model is a _tree model_ if it can be represented as a tree-like graph, which has only one root, viz. a node without parent, and every child node below the root has only one parent.

(2) Consider a simple _ALC_ T-box T<sup>2</sup>={$Daughter \sqsubseteq Female$, $Son \sqsubseteq Male$}. The _ALC_ concept $Father$ is satisfiable with respect to T<sup>2</sup>, and it is not difficult to find that $Father$ has a tree model with respect to T<sup>2</sup>. For example, $I_2=(\bigtriangleup^2,.^2)$ such that:
(2) Consider a simple _ALC_ T-box T<sup>2</sup>={$Daughter\sqsubseteq Female$, $Son \sqsubseteq Male$}. The _ALC_ concept $Father$ is satisfiable with respect to T<sup>2</sup>, and it is not difficult to find that $Father$ has a tree model with respect to T<sup>2</sup>. For example, $I_2=(\bigtriangleup^2,.^2)$ such that:

$\bigtriangleup^2$={Karl,Mary,Jack,Lucy}

Expand All @@ -271,27 +271,28 @@ It is clear that $I_2$ is a model of T<sup>2</sup>, and $Father$ has an instance

(3) TMP is crucial to tableau-based algorithms for the consistency check of knowledge base and applied ontology. Most of applied ontologies, especially those BFO-based ones, have TMP, allowing that their consistency can be checked by tableau reasonings. Moreover, TMP can show decidability of satisfiability of ALC concepts in the so-called automata-based approach.

However, if a knowledge base or ontology has only infinite tree models, then TMP might not be very useful in consistency check.
However, if we deal with linear roles or small datasets, TMP might not be very useful because its poor generalization performance in these cases.

**[9]** Open the Protege editor and create object properties for each of the role names that you constructed in question 1. You should have at least 6 object properties. Assert in the editor that P is a sub-property of O, that P is transitive, and that O is symmetric. Next, add individuals - a, b, c - to the file and assert that c is part of a and that c overlaps b. Running the reasoner should reveal - highlighted in yellow if you select the individual c - that c overlaps a. Using the discussion in the selections from chapter 4 of the Baader, et. al. text as a guide, explain how the tableau algorithm is generating this inference. Also, provide a screenshot of the results of your reasoner run with c highlighted.

Answer:

![picture 1](pic_1_1.PNG)
![picture 1](https://github.com/peihongx/PHI-696/blob/main/Project-2/pic_1_1.PNG)

![picture 1](pic_1_2.PNG)
![picture 1](https://github.com/peihongx/PHI-696/blob/main/Project-2/pic_1_2.PNG)

![picture 1](https://github.com/peihongx/PHI-696/blob/main/Project-2/pic_1_3.PNG)

![picture 1](pic_1_3.PNG)

The tableau algorithm generates this inference (c,a):O in such a way:

From Theorem 2.17 (Baader.etc: 32), we have $(\emptyset,A)\models(c,a):O$ iff ($\emptyset$,$A\cup$ {(c,a):¬O}) _is_ not consistent. Here A={(c,a):P,(c,b):O}.
From Theorem 2.17 (Baader.etc: 32), we have $(\emptyset,A)\models(c,a):O$ iff ($\emptyset,A\cup$ {(c,a):¬O}) _is_ not consistent. Here A={(c,a):P,(c,b):O}.

Therefore, the target inference problem becomes the problem of determining that the new A-box $A^*$={(c,a):P,(c,b):O, (c,a)¬O} is inconsistent.
Therefore, the target inference problem becomes the problem of determining that the new A-box A*={(c,a):P,(c,b):O, (c,a)¬O} is inconsistent.

In order to calculate with the inconsistency problem, the algorithm _expand_ will first apply concept expansion rules to $A^*$ to construct a complete A-box. However, as we notice, $A^*$ does not include any concept, so the application of expansion rules to $A^*$ is empty.
In order to calculate with the inconsistency problem, the algorithm _expand_ will first apply concept expansion rules to A* to construct a complete A-box. However, as we notice, A* does not include any concept, so the application of expansion rules to A* is empty.

However, by the fact that P is a sub-property of O and that (c,a):P, the algorithm _expand_ infers that (c,a):O, and thus finds that $A^*$ implies a clash {(c,a):O, (c,a):¬O}. Thus, $expand(A^*)= \emptyset$.
However, by the fact that P is a sub-property of O and that (c,a):P, the algorithm _expand_ infers that (c,a):O, and thus finds that A* implies a clash {(c,a):O, (c,a):¬O}. Thus, $expand(A^*)= \emptyset$.

In light of this, a larger alrorithm _consistent_ which includes the algorithm _expand_ will return "inconsistent". Given Theorem 2.17, we have shown that $(\emptyset,A)\models(c,a):O$.

Expand All @@ -307,8 +308,8 @@ Provide a screenshot of your results here.

Answers:

![picture 2](pic_2_1.PNG)
![picture 2](https://github.com/peihongx/PHI-696/blob/main/Project-2/pic_2_1.PNG)

![picture 3](pic_2_2.PNG)
![picture 3](https://github.com/peihongx/PHI-696/blob/main/Project-2/pic_2_2.PNG)

![picture 4](pic_2_3.PNG)
![picture 4](https://github.com/peihongx/PHI-696/blob/main/Project-2/pic_2_3.PNG)

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