30   other hand, store local data for a task at hand. They act like the

    30   other hand, store local data for a task at hand. They act like the

    31   ``short-term memory'' and there can be many of them that are active in

    31   ``short-term memory'' and there can be many of them that are active in

    32   parallel.

    32   parallel.

    33 *}

    33 *}

    34 

    34 

    36 

    36 

    37 text {*

    37 text {*

    38   Theories, as said above, are the most basic layer of abstraction in

    38   Theories, as said above, are the most basic layer of abstraction in

    39   Isabelle. They record information about definitions, syntax declarations, axioms,

    39   Isabelle. They record information about definitions, syntax declarations, axioms,

    40   theorems and much more.  For example, if a definition is made, it

    40   theorems and much more.  For example, if a definition is made, it