Richard Costa — writing https://richard-costa.github.io/writing.html Essays, notes, and posts by Richard Costa. quarto-1.10.18 Sat, 26 Sep 2026 21:14:33 GMT Introduction to Logic https://richard-costa.github.io/notes/logic/introduction.html https://richard-costa.github.io/notes/logic/introduction.html Sat, 26 Sep 2026 21:14:33 GMT Dirac Notation and Riesz Theorem https://richard-costa.github.io/notes/quantum-mechanics/dirac-riesz.html https://richard-costa.github.io/notes/quantum-mechanics/dirac-riesz.html Sat, 26 Sep 2026 21:14:33 GMT Review of Quantum Mechanics https://richard-costa.github.io/notes/quantum-mechanics/review.html https://richard-costa.github.io/notes/quantum-mechanics/review.html Sat, 26 Sep 2026 21:14:33 GMT Installing and updating Quarto on Arch Linux https://richard-costa.github.io/notes/linux/quarto-on-arch.html https://richard-costa.github.io/notes/linux/quarto-on-arch.html Sat, 26 Sep 2026 21:14:33 GMT Using the SDDM Astronaut theme https://richard-costa.github.io/notes/linux/sddm-astronaut-theme.html https://richard-costa.github.io/notes/linux/sddm-astronaut-theme.html Sat, 26 Sep 2026 21:14:33 GMT YAD calendar popup for Waybar https://richard-costa.github.io/notes/linux/waybar-yad-calendar.html https://richard-costa.github.io/notes/linux/waybar-yad-calendar.html Sat, 26 Sep 2026 21:14:33 GMT Music for an Elderly Elephant https://richard-costa.github.io/posts/20260520-elephant.html wholesome https://richard-costa.github.io/posts/20260520-elephant.html Wed, 20 May 2026 03:00:00 GMT