This is an open-ended project to formalize mathematics using the type theory of Agda programming language. Currently, I am focusing on formalizing Group Theory. My current long-term goal is to formalize a significant portion of undergraduate algebra (group, ring, field, module and Galois theories), basic algebraic geometry (curves, surfaces, Grassmanian varieties) and probability theory.

You can see the proofs without needing any special software; although identifiers make use of Unicode characters (such as ∀, ∃, 𝔄, →), so, you should be able to see them.

You need Agda version >=2.5.3 to check proofs, this is the only dependency. Run:

make check

This command will run agda --safe on all source files. You can confirm that all proofs are checked by Agda. Since classical and constructive theorems are separated via modules, agda can be run on --safe mode which makes sure I don't lead myself to contradiction.

All my work is released under GNU GPLv3 . You're welcome to study, change, redistribute, share all my proofs.

Basic logical connectives and quantifiers are defined. Basic theorems are proved.

Defined group. Defined group order, group homomorphism, group isomorphism, group action, subgroup and group centralizer. Defined quotient group.

Proved theorems:

Completed all standard group bookkeeping theorems:

• Identity is unique
• For each element, its inverse is unique
• (a⁻¹)⁻¹ = a
• (a · b)⁻¹ = b⁻¹ · a⁻¹

Subgroup Theorems:

• Subgroup criterion
• Centralizer is a subgroup

Quotient Group:

• Proved that cosets of normal subgroups form a group