Darij Grinberg

Karlsruhe (Germany) / Minneapolis, Minnesota (USA)

Email address:
where the letter A should be replaced by darijgrinberg
and the sign = by the sign @.
(Apologies for this obstruction; I am trying to protect my mailbox against spammers
automatically searching for everything that looks like an email address.)

about | new | algebra
qedmo | lambda | hopf
geo1 | geo2 | solutions | german

last update 4 Nov 2016
recent additions

This site is moving!

From 2017 on, this site will no longer be hosted on MIT's servers. It will still be available at

This is a website for mathematics, from elementary to advanced. Formerly, it used to be entirely dedicated to the Geometry of the Triangle; this has now been moved to two subpages: Geometry Publications and Geometry Unpublished Notes. I am currently working on combinatorial algebra and representation theory, so do not expect any more geometry to appear here, but new notes on algebra will surface from time to time.

About me and this website (this includes a FAQ and instructions on opening the files on this site).


Some advanced algebra (work in progress), Lambda-rings and Hopfalgebren (lecture notes after Prof. Hans-Jürgen Schneider, in German)

German papers on Elementary Mathematics / Deutschsprachige Aufsätze über Elementarmathematik
(inkl. Arbeiten über Elementargeometrie und Lösungen von Wettbewerbsaufgaben)

Elementary Geometry: Publications and Unpublished notes

Solutions to review problems
(Some problems from American Mathematical Monthly and other sources, with my solutions.)

Other works

A few texts I have written for diverse purposes, arranged according to potential usefulness (i. e., the first in the list are probably the most useful).


Texts written for internet forums:
- MO65420 (sourcecode). This shows some properties of alpha-equivalence and substitution in lambda-calculus that were required for MO question #65420. Already partly obsolete.