more robust, for the sake of very rare duplicate files: src/Doc/Prog_Prove/MyList.thy and $AFP/Case_Labeling/util.ML;
chapter_definition HOL
description "
Higher-Order Logic.
Isabelle/HOL is a version of classical higher-order logic resembling
that of the HOL System (https://www.cl.cam.ac.uk/Research/HVG/HOL).
"
chapter_definition FOL
description "
First-Order Logic with some variations: single-sorted vs. many-sorted
(polymorphic), classical vs. intuitionistic, domain-theory (LCF) vs.
set-theory (ZF).
"
chapter_definition Pure
description "
The Pure logical framework.
Isabelle/Pure is a version of intuitionistic higher-order logic that
expresses rules for Natural Deduction declaratively.
"
chapter_definition Misc
description "
Miscellaneous object-logics, tools, and experiments.
"
chapter_definition Doc
description "
Sources of Documentation.
"
chapter_definition Unsorted
description "
Sessions without 'chapter' declaration.
"