Miika Rankaviita
Exercise 4.1 in Hartshorne's Deformation Theory

I was reading about first order deformations from Hartshorne's Deformation Theory some time ago, and was thrown off by a small mistake in one of the exercises. Exercise 4.1 in section 4 of chapter 1 asks to prove that if a k-algebra endomorphism f: A → A of a local k-algebra with residue field k induces an isomorphism A/m² → A/m², …


My Math Camp 2025 activity

Aalto University hosts an annual maths camp for upper secondary school students of ages 16-18, and I was kindly granted two 1 hour sessions in the camp this year. Given this unique and exciting opportunity, I wanted to give my best shot at designing a fun activity for the students. Since accomplishing anything requires a solid plan, I first asked …


Localisation by adjunctions

One of the hardest modules I took at Imperial was MATH70061 Commutative Algebra taught by Yankı Lekili. What made the module so challenging was the fact that we had to submit solutions to 6-8 tedious homework problems every 2 weeks. In addition, the course covered quite a broad selection of material, which we had to stay on top of. The …


Why line bundles in algebraic geometry?

Morphisms between affine varieties are determined simply by specifying a fixed number of polynomials. On the other hand, morphisms between projective varieties are not as easy to deal with in general and may sometimes require construction via gluing. If one tries to understand collections of morphism, it becomes tricky to keep track of all the "gluing data". This problem is …


My Favourite Theorem

I decided to start this blog by writing about my favourite proof that can be fit in a blog post and which put me on the track to learn algebraic geometry. I was originally fascinated by the connections that algebraic geometry makes between branches of mathematics and uses these to solve actual problems, which is what I saw nicely demonstrated …