*"From error to error one discovers the entire truth."*
- Sigmund Freud

When I have some time (when I retire?) I would like to collect in this page the most interesting incorrect proofs and algorithms in the field of geometry. Like psychologists with illusions, I am fascinated by those things that don't work as we expect them to, and why they don't. In the mean time, below are some interesting references.

**Proofs:**

- Scientific Practice and Thinking - A Course
- The International Newsletter on Teaching and Learning Mathematical Proof*Proof*- PLUS - A great math thinking site
- L. I. Golovina and I. M. Yaglom,
*Induction in Geometry*, Mir Publishers, Moscow, 1979. [Examples of how to prove geometry theorems using induction.] - A. I. Fetisov,
*Proof in Geometry*, Mir Publishers, Moscow, 1978. [A nice elementary discussion on what is a proof, when and why it is necessary and what things may be accepted without proof.] - I. Kleiner and N. Movshovitz-Hadar, "Proof: A
Many-Splendored
Thing,"
*The Mathematical Intelligencer*, vol. 19, No. 3, Summer 1997, pp. 16-26. [A fascinating historical perspective on proving things.] - Selected publications on Proof

**Refutations:**

- Bryan Bunch, Mathematical Fallacies and Paradoxes, Dover publications, Inc., Mineola, New York, 1982.
- Ya. S. Dubnov, Errores en las Demostraciones Geometricas, Rubinos, Madrid, Spain, 1993. (in Spanish)
- Common errors in mathematics