Merge pull request #48 from ProjetPP/restrict_full_triple

Improve datamodel

.gitignore

@@ -0,0 +1,20 @@
+*~
+*.aux
+*.bbl
+*.blg
+*.log
+*.synctex
+*.out
+*.dvi
+*.bak
+*.xcf
+*.rej
+*.nav
+*.toc
+*.snm
+*.gz
+*.ps
+*.pyg
+*.vrb
+*.backup
+*.pdf

data-model.md

@@ -37,7 +37,7 @@ A *triple*, as in RDF, is a structure composed of three elements:
 We use triple formalism with some operators:
 
 ##### *full triple*
-*Full triple* is a function of *list × list × list → bool* written `(la, lb, lc)` that returns `true`, if and only if, for all `a` ∈ `la`, `b` ∈ `lb` and `c` ∈ `lc`, `(a, b, c)` is true.
+*Full triple* is a function of *list × list × list → bool* written `(la, lb, lc)` that returns `true`, if and only if, for all `a` ∈ `la` and `c` ∈ `lc`, there __exists__ `b` ∈ `lb` such that `(a, b, c)` is true.
 
 ##### *triples with hole*
 The aim of *triples with hole* is to get information. They are functions of *list × list → list*. We define two of them:
@@ -57,10 +57,12 @@ The *union* is an operator of *list⁺ → list* that returns the union of the l
 The *intersection* is an operator of *list⁺ → list* that returns the intersection of the lists. Its notation is the infix `∩`.
 
 ##### *sort*
-*Sort* is an operator of *list × resource → list*, written `sort(l, a)`, which sorts the *list* `l` with increasing order according to the predicate `a`.
+*Sort* is an operator of *list × resource → list*, written `sort(l, a)`, which sorts the *list* `l` with increasing order according to the predicate `a`. A `default` predicate can be used when the question does not contain information about it.
 
 Example: `sort([Theodore Roosevelt, George Washington], birth date)` returns `[George Washington, Theodore Roosevelt]`.
 
+Example of `default`: The question "Who is the first president of France" may be formalized as `sort((France, president, ?), default)`.
+
 ##### *first*
 *First* is an operator of *list → resource*, written `first(l)`, that returns the first element of the list.
 
@@ -84,15 +86,15 @@ The *or* is an operator of *bool⁺ → bool* that returns true if the disjoncti
 The *not* is an operator of *bool → bool* that returns the negation of the parameter. Its notation is the prefix `¬`.
 
 #### *exists*
-The *exists* is an operator of *list → bool* that returns *true* if, and only if, there exits a *resource* in the *list* e.g. the *list* is not empty. Its notation is the prefix `∃`.
+The *exists* is an operator of *list → bool* that returns *true* if, and only if, there exits a *resource* in the *list* (i.e. the *list* is not empty). Its notation is the prefix `∃`.
 
-Example: The question "Is there a pink bird" may be formalized as `∃ (?, instance of, bird) ∩ (?, color, pink)`.
+Example: The question "Is there a pink bird?" may be formalized as `∃ (?, instance of, bird) ∩ (?, color, pink)`.
 
 
 ## Extensions to the data model
 
 ### *sentence* *value*
-A *sentence* represents a full question encoded as a string. Its notation is a string between quotation marks like `"Who are you"`. It may be only the root of the question tree.
+A *sentence* represents a full question encoded as a string. Its notation is a string between quotation marks like `"Who are you?"`. It may be only the root of the question tree.
 
 ### Typing
 It is possible to add type information to *resource* and *missing* nodes.
@@ -104,7 +106,7 @@ Example: If we choose as range "musician" for the *resource* node `Michele Smith
 ## JSON serialization
 We provide a canonical representation of the data model in [JSON](http://www.json.org).
 
-Each node of the query tree is encoded as a JSON object with an attribute `type` that determine the kind of node and the other attributes.
+Each node of the query tree is encoded as a JSON object with an attribute `type` that determines the kind of node and the other attributes.
 
 The `type` attributes has the same value as the name of the node type in the data model.
 
@@ -114,7 +116,7 @@ Here are the serialization for the possible nodes:
 The `resource` serialization has three primary attributes:
 * `value` that is a string representation of the resource (for interoperability).
 * `value-type` (optional) that adds information about the type of the entity. Each module can use its own types or use basic types specified just after. Default: `string`.
-* `range` (optional) used in order to contains type informations as specified by the typing extension of the data model.
+* `range` (optional) used in order to contain type informations as specified by the typing extension of the data model.
 
 There may be additional attributes depending on the `value-type`.
 
@@ -219,7 +221,7 @@ Note: You must use as value of *[schema:sameAs](http://schema.org/sameAs)* only
 ```
 
 ### *list*
-It as only one attribute, `list` that is an array that stores the serialization of *list* elements.
+It has only one attribute, `list` that is an array that stores the serialization of *list* elements.
 
 Example: The serialization of `[George Washington, Theodore Roosevelt]' is
 ```
@@ -256,7 +258,7 @@ Example: the serialization of the triple `(George Washington, birth date, ?)` is
 ```
 
 ### *union*, *intersection*, *and* and *or*
-There is only one parameter, *list* that is an array containing the operator parameters.
+There is only one parameter, *list*, that is an array containing the operator parameters.
 
 Example: the serialization of the query `[George Washington] ∪ [Theodore Roosevelt]` is:
 ```
@@ -269,7 +271,7 @@ Example: the serialization of the query `[George Washington] ∪ [Theodore Roose
 ### *sort*
 There are two parameters:
 * `list` the input *node*.
-* `predicate` the predicate with which the *list* is sorted.
+* `predicate` the predicate used to sort the *list*.
 
 Example: the serialization of the query `sort([Theodore Roosevelt, George Washington], birth date)` is:
 ```
@@ -292,7 +294,7 @@ Example: the serialization of the query `first([George Washington, Theodore Roos
 ```
 
 ### *sentence*
-Has only one attribute, `value` that contains the sentence.
+It has only one attribute, `value` that contains the sentence.
 
 Example: The serialization of `"Who is George Washington?"` is:
 ```