diff --git a/7-sketches/7-sketches.org b/7-sketches/7-sketches.org
index 4c14cae..5066733 100644
--- a/7-sketches/7-sketches.org
+++ b/7-sketches/7-sketches.org
@@ -602,3 +602,18 @@ TODO is it possible to have more $\Ob(\cat{E})$ and/or $\Mor(\cat{E})$?
 tool for tracking locally defined data
 
 *** Presheaf: Functor \(F: \cat{C}\op \to \SmSet\)
+
+
+* Compactness
+shape property
+https://www.youtube.com/watch?v=td7Nz9ATyWY
+
+Elements of a Topology form Open sets -
+See Also https://www.youtube.com/watch?v=td7Nz9ATyWY&t=719
+
+
+Functorial Semantics
+C - category of syntactic expressions
+D - category meanings 
+F: C -> D - functor sending an expression to it's meaning. I.e. it's the way
+how to give meaning i.e. how to interpret the syntactic expression
diff --git a/notes/guix-guile-nix/guix_package.scrbl b/notes/guix-guile-nix/guix_package.scrbl
index c503cb6..90eced2 100644
--- a/notes/guix-guile-nix/guix_package.scrbl
+++ b/notes/guix-guile-nix/guix_package.scrbl
@@ -384,3 +384,59 @@
   (package? p)
   (package-name p)
 }
+
+@block{@block-name{Nix to Guix}
+  Functional Package Management with Guix; Ludovic Courtès, 2013
+  https://arxiv.org/pdf/1305.4584.pdf
+  Like Guix and Nix, Vesta is a purely functional build system [11]
+  
+  Scsh provides a complete interface to substitute Scheme in “shell programming” tasks [18].
+  
+  Nickel is an evolution of the Nix language, while trying to overcome some of its limitations.
+  https://github.com/tweag/nickel
+  Nickel grammar for tree-sitter.
+  https://github.com/nickel-lang/tree-sitter-nickel
+  
+  https://nixos.wiki/wiki/Packaging/Tutorial
+  
+  nix-service-type
+  runs build daemon of the Nix package manager. Which 'would allow you to use
+  Nix's Firefox package'
+  
+  Example how to use it:
+  (use-modules (gnu))
+  (use-service-modules nix)
+  (use-package-modules package-management)
+  ;;
+  (operating-system
+    ;; ...
+    (packages (append (list nix)
+                      %base-packages))
+    (services (append (list (service nix-service-type))
+                      %base-services)))
+  After `guix system reconfigure` configure Nix for your user:
+  Add a Nix channel and update it. See Nix Package Manager Guide. 
+  
+  Tree-sitter
+  An incremental parsing system for programming tools
+  https://github.com/tree-sitter/tree-sitter
+  
+  TODO ChatGPT search for
+  - parsing the Nix DSL (racket FTW?)
+  - porting packages from Nix to Guix
+  
+  Declaratively yours: Composing system abstractions with GNU Guix
+  https://archive.fosdem.org/2021/schedule/event/gnuguix/
+  
+  Learning Nix:
+  Peering into the Land of Parentheses - Guix from the Nix Perspective (NixCon 2019)
+  https://www.youtube.com/watch?v=bDGzCXr6VYU
+  
+  generate environment modules, as commonly used in high-performance computing (HPC) on shared clusters
+  https://gitlab.inria.fr/guix-hpc/guix-modules
+  `guix module create` ???
+  
+  racket2nix generate a Nix derivation for your Racket package
+  Take an info.rkt file, produce a info.nix file. 
+  https://github.com/fractalide/racket2nix
+}