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+YAP Core Built-ins					{#core}
+=================
+
+This chapter describes the core predicates  that control the execution of
+Prolog programs, provide fundamental functionality such as termm manipulation or arithmetic, and support interaction with external
+resources, Many of the predicates described here have been standardised by the ISO. The standartised subset of Prolog also known as ISO-Prolog.                                                                                                                                                                                              
+
+In the description of the arguments of predicates the following
+notation will be used:
+
++ a preceding plus sign will denote an argument as an "input
+argument" - it cannot be a free variable at the time of the call;
++ a preceding minus sign will denote an "output argument";
++ an argument with no preceding symbol can be used in both ways.
+
+
+@copydoc builtins
+
+
+@{
+@defgroup builtins YAP Core Builtins:
+
+@}
+