Rank–nullity theorem
Kernel and image dimensions sum to domain dimension.
Key knowledge
For a linear map T:V→W with finite-dimensional V, dim V = dim ker T + dim im T. Rank is the image dimension and nullity is the kernel dimension.
Values and equations
dim V = dim ker T + dim im T
- T
- Linear map V→W
- ker T
- Vectors sent to zero
- im T
- Image of T
Conditions and scope
- V and W are vector spaces over the same field.
- The equality is not a subtraction rule for arbitrary infinite cardinal dimensions.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Physical pages 5–6 vector-space axioms; page 14 kernel, image and rank-nullity.
2026-10-10 · Finite-dimensional rank–nullity statement.
Entry details
Permanent link to this entry ↗- Record identity
- math-rank-nullity
- Revision
- university-reference.1
- Structured reference record
- University reference