# Verification Strategies
vyre-conform uses independent verification strategies. Each one catches a
different class of defect, and passing all of them produces stronger evidence
than passing any single strategy.
## Parity
Parity verification compares backend output bytes to CPU reference output
bytes for generated, boundary, adversarial, and regression inputs. It proves
that the backend matches the point truth for every input the suite executed.
## Algebraic
Algebraic verification checks every declared `AlgebraicLaw` for each operation.
It verifies structural truth: commutativity, associativity, identities,
self-inverse behavior, boundedness, distributivity, and other registered laws.
## Compositional
Compositional verification checks chains of operations. If operation `A` is
correct and operation `B` is correct, then the composed program `B(A(x))` should
also be correct. This catches calling convention, byte layout, buffer reuse,
and cross-operation bugs that primitive tests do not see.
## Invariant
Invariant verification checks engine-level properties such as determinism, no
lost output, no duplicate output, ordered output, bounded resources,
termination, atomic linearizability, and workgroup-size independence.
## Determinism
Determinism verification runs the same valid input multiple times and requires
identical output bytes. It catches data races, uninitialized output, scheduling
dependence, and backend state leakage between dispatches.
## Performance
Performance verification records throughput baselines under the conformance
configuration. Performance is not a substitute for correctness, but production
conformance requires that a backend is correct and fast enough to be usable.
## Independence
Each strategy is independent. A backend can pass parity and fail algebraic
checks. It can pass primitive algebra and fail engine invariants. It can be
correct for one dispatch and nondeterministic across repeats. L4 conformance
requires the combined result because internet-scale correctness needs multiple
orthogonal checks.