# General Environment Description Language
## 6 Occurrences in GEDL Language  
In this section, the following elements of the GEDL language are defined: occurrences, the feature usage, the feature set usage, the action, the instance, the relationship, and the instance concept membership. **Definition 12**. : _Occurrences oOC--is an JSON object containing a finite set of instances and relationship occurrences observed by the individual. Occurrences include:_  
1{
2\"instances\": aIN,
3\"relationships\": aRS
4},  
* _aIN--is a JSON array containing a finite set of instances of \(aIN^{o}=(oI^{o}_{1},...,oI^{o}_{f})\),_
* _aRS--is a JSON array containing a finite set of relationships oR, \(aRS^{o}=(oR^{o}_{1},...,oR^{o}_{K})\),_  
_where \(o\)1 is defined in Definition 16, and oR is defined in Definition 17._\(oOC=aIN\times aRS,oOC^{o}=elem(IK^{o},oOC),IK^{o}\in I\!K\). **Definition 13**. : _A feature usage of \(e\)U is an JSON object representing values assigned to the existing feature \(o\)F of the instance \(o\)1. The \(o\)FU is composed of the following elements:_  
```
1{
2\"name\":oFName,
3\"value\":oFUValue,
4}
```  
_where:_  
* _oFName_--_is a JSON string representing the name of the feature \(o\)F existing in the conceptual system \(oCS\)_,_ \(\exists oF^{o}:oFName^{o}=elem(oF^{o},oFName)\wedge oF^{o}\in\widehat{aF^{o}} \wedge aF^{o}=elem(oCS^{o},aF)\wedge oCS^{o}=elem(IK^{o},oCS),IK^{o}\in I\!K\)_._
_oFUValue_--_is a JSON value assigned to the feature from the \(o\)_FDomain of_ \(o\)_F_,_ \(\exists oF^{o}:oFName^{o}=elem(oF^{o},oFName)\wedge oFDomain^{o}=elem(oF^{o},oFDomain)\wedge oFUValue^{o}\in oFDoFDomain^{o}\wedge oF^{o}\in aF^{o}\wedge aF^{o}=elem(oCS^{o},aF)\wedge oCS^{o}=elem(IK^{o},oCS)\wedge IK^{o}\in I\!K\)_._  
The example of the usage of three features is presented below:  
```
1\"features\":[{
2\"name\":\"tastiness\",
3\"value\":0.3
4},
5{
6\"name\":\"weight\",
7\"value\":50
8},
9{
10\"name\":\"bloodGroup\",
11\"value\":\"A\"
12}]
```  
**Definition 14**. : _The feature set usage of \(e\)SU is an JSON object representing values assigned to the existing feature set \(o\)FS. The \(o\)FSU is:_  
```
1{
2\"name\":oFNAME,
3\"values\":aFSUvalues
4},
```  
_where:_  
* _oFNAME_--_is a JSON string containing a name of the feature set \(o\)FS existing in \(o\)CS_,_ \(\exists oFS^{o}:oFNAME^{o}=elem(oFS^{o},oFNAME)\wedge oFS^{o}\in\widehat{aFS^{o}} =elem(oCS^{o},aFS)\wedge oCS^{o}=elem(IK^{o},oCS)\wedge IK^{o}\in I\!K\)_,_
* _aFSUvalues_--_is a JSON array containing an ordered set of values assigned to features in the feature set,_ \(aFSUvalues^{o}=(oFSUValue^{o}_{1},...,oFSUValue^{o}_{p},...,oFSUValue^{o}_{p})\)_._ _All of the values should belong to the domains of the features,_ \(\forall_{p\in\{1,...,p\}}\exists oF^{o}_{p}\exists oFS^{o}:oF^{o}_{p}\in aF^{o} =elem(oCS^{o},aF)\wedge oFS^{o}\in aFS^{o}=elem(oCS^{o},aFS)\wedge oFName^{o}=elem(oFS^{o},oFNAME^{o}_{p}=elem(oFS^{o},aFNames)\wedge oFName^{o}_{p}=elem(oFS^{o},oFName)\wedge oFName^{o}_{p}=elem(oFS^{o},oFName)\wedge oFDomain^{o}_{p}=elem(oF^{o}_{p},oFDomain)\wedge oFName^{o}_{p}=elem(oFS^{o},oFDomain)\wedge oFName^{o}_{p}=elem(o\(oFUlValue_{p}^{o}\in oFD_{oFDomain}\wedge oCS^{o}=elem(IK^{o},oCS)\wedge IK^{o}\in IK\), where \(P=card(aF\widehat{SUvalues^{o}})\), function \(card()\) return number of elements of a set. \(oFSU=oFSName\times aFSUvalues\). The example of the feature set usage is presented below:  
```
1{
2\"name: \"color\",
3\"values\": [255, 20, 60]
4}
```  
**Definition 15**. : _An action \(oA\) is a JSON object containing a description of an action, which can be potentially performed by the instance to which it is assigned, and result in a change in the state of the fragment of \(IK^{o}\). An instance uses its own capabilities to carry out an action. It can also use other instances and their actions.