The matrix multiplication exponent over a field
is the infimum of the exponents
such that, for every
, two
matrices over
can be multiplied with
arithmetic operations. The constant
in the big-O notation may depend on
but not on
. The operations counted are addition,
subtraction, and multiplication
of elements of the field; their bit
complexity is a different question.
The usual matrix multiplication algorithm uses
operations. Recursive use of Strassen's formulas
gives
The lower limit 2 comes from the entries of a general product, and the conjecture
that
remains open. The exponent describes asymptotic growth
and does not by itself determine which algorithm is
fastest at a given finite size (Strassen 1969).
OpenAI (2026a) announced
Equivalently, the claim gives arithmetic operations for every
over the complex
numbers. It does not claim this bound over every field,
a practical crossover size, or an improvement in bit
complexity. The release attributes the argument to an unreleased internal OpenAI
model and supplies a Lean formalization of the bound. As of Oct. 7, 2026, VibeMathed
(2026) had read the formal statement but had not independently rebuilt it, and independent
specialist verification of the complete proof had not been
reported.
A separate announcement by OpenAI (2026c) gives over every fixed field
,
including every positive characteristic. This
bound has broader field scope than the sharper complex-number
bound above. Both statements count arithmetic operations. The release proofs
have not been independently verified here.
OpenAI (2026b) separately announced over every field of
characteristic zero and over all positive characteristics
outside one finite exceptional set.
In characteristic zero, the same manuscript claims
that multiplying an
matrix by an
matrix requires
arithmetic operations, and that the corresponding
exponent for
by
multiplication is less than 2.092. The latter
rectangular bound also has the finite-exception transfer
to positive characteristic; the 0.465 claim does
not assert that transfer.