# validator_emission (/docs/hyperparameters/validator-emission)

Slot 3 of the [emission weight vector](/docs/concepts/emission-weights):
the fraction of each block's `alpha_out` that becomes validator dividends.
Root TAO stakers are paid their baseline share out of this slot first; alpha
validators share the rest. Stored as `u64` parts of `u64::MAX`.

## How it works [#how-it-works]

Per block, `alpha_out × validator_emission` goes to the validator bucket.
Root's **baseline share** `r = V0 × x / (x + A)` — `V0` the default 41%
validator share, `x = root_tao × TaoWeight`, `A` the subnet's alpha
issuance, recomputed every block — is set aside for root TAO stakers as
`min(validator_emission, r) × alpha_out`, and the rest is distributed through
Yuma Consensus dividends at the epoch
([Root off the top](/docs/concepts/emission-weights#root-off-the-top)).
Root therefore earns what it would on an untouched subnet whatever this slot
is set to; moving the slot only changes what alpha validators receive.

## Bounds [#bounds]

`validator_emission ≤ 0.50`, and the new value must be **strictly above**
root's baseline share `r` at the block of the call, or alpha validators would
receive nothing. On a mainnet subnet with 5.4M TAO on root, 6.5M alpha
issued and `TaoWeight = 0.18`, `r` is about 5.40%. The floor moves with root
stake, issuance and the global weight, so `btcli subnets emission show`
prints the current value. If the baseline later grows past the slot, root's
cut is capped at the whole slot and alpha validators get nothing until the
owner raises it. Errors: `ValidatorEmissionAboveMaximum`,
`ValidatorEmissionTooLowToPreserveRoot`, `EmissionWeightsDoNotSumToOne`.

## Reading and setting [#reading-and-setting]

```bash
btcli subnets emission show --netuid 12          # prints the current floor
btcli subnets emission decrease --netuid 12 --slot validator --by 0.05
```

Settable by the subnet owner (once per week per subnet) or root through
[`set-subnet-emission-weights`](/docs/tx/set-subnet-emission-weights); not
available on the root subnet.

## Related [#related]

* [`owner_emission`](/docs/hyperparameters/owner-emission),
  [`miner_emission`](/docs/hyperparameters/miner-emission)
* [Emission weights](/docs/concepts/emission-weights)