Emission weights

Every subnet carries a five-slot emission weight vector

[burn, recycle, owner, validator, miner]

that says how each block's alpha emission is divided. Each slot is a u64 share of u64::MAX, so the five slots sum to exactly one. The subnet owner (or root) sets it with set-subnet-emission-weights; anyone reads it with subnet-emission-weights or btcli subnets emission show.

New subnets start at the historical split — [0, 0, 0.18, 0.41, 0.41] on mainnet — so nothing changes until an owner decides it should.

What each slot does

The owner slot at zero means "no owner cut"; the legacy owner_cut_enabled hyperparameter is now simply owner > 0. Burn and recycle are present in the vector so the format does not change when they are enabled later, but a non-zero value in either is rejected today.

Per block, alpha_out × owner accrues to the owner, alpha_out × validator to the validator bucket and alpha_out × miner to the miner bucket. Root's share is carved out of the validator bucket by the subnet's consensus-side root proportion (consensus_root_proportion in block_step.rs), so shrinking the validator slot would, on its own, shrink what root TAO stakers receive. The effective TAO weight below prevents that.

The effective TAO weight

Root TAO is weighted against alpha by a TAO weight w. Each block, root's alpha on a subnet is

root_alpha = V × x / (x + A) × alpha_out        with x = root_tao × w

where V is the validator slot and A the subnet's alpha issuance. Every subnet carries its own effective TAO weight w_s (SubnetTaoWeight), used on the consensus side of that subnet only: the root share carved out of the validator slot, the TAO-vs-alpha split of validator dividends, and the stake weighting inside Yuma Consensus. A subnet with no entry simply follows the global TaoWeight (0.18 on mainnet today), exactly as before emission weights existed.

Every accepted set call solves w_s once, at that block, from live chain values and the new validator slot alone:

1. root's baseline share of emission, r = V0 × x_g / (x_g + A) with x_g = root_tao × TaoWeight — what root would earn on this subnet right now with the default validator share V0 (0.41 on mainnet, derived from the default owner cut) and the global TaoWeight;
2. the weight that pays r under the new slot, x_new = r × A / (V_new − r), w_s = x_new / root_tao.

Root TAO stakers therefore earn, the block after any change, exactly what an untouched subnet would pay them at that block. The solve never reads the old vector or the old w_s, so an owner cannot ratchet root's share by raising V while the subnet is young and lowering it later: the target is recomputed from scratch every time, and a round trip (raise V, let issuance grow, lower it back) lands on the same w_s as making the final change in one step. Afterwards w_s is left alone and everything scales with stake and issuance as usual, until the next set. Setting V back to exactly V0 clears the entry, so the subnet follows the global TaoWeight again (the solve would land there anyway).

The weight is capped at one — root TAO never counts more than 1:1 against alpha — so not every V is reachable. The call fails with ValidatorEmissionTooLowToPreserveRoot when V_new ≤ r or the solved weight would exceed one; equivalently the floor at this block is r × (1 + A / root_tao). On a mainnet subnet with 5.4M TAO on root, 6.5M alpha issued and TaoWeight = 0.18, the validator share can go down to about 11.8%. The floor moves with root stake, issuance and the global weight, so btcli subnets emission show prints the current value. With no root stake or no alpha issued there is nothing to preserve: any valid V is accepted and w_s is untouched.

The pool side never sees w_s. tao_in, alpha_in and the alpha-injection cap in get_subnet_terms use the pool-side root_proportion with the global TaoWeight, exactly as before emission weights existed. Changing a subnet's vector changes how its alpha is distributed; it does not change how much TAO or alpha is injected into its pool.

Changing the vector

Updates are sparse: name the slots you are changing and their new shares; omitted owner/validator/miner slots keep their current value. Because the five slots must still sum to one, lowering one slot means raising another in the same call. btcli does the arithmetic:

# see the vector, root's share and baseline, every allowed range, and the next change window
btcli subnets emission show --netuid 12

# set one slot; the other two are rescaled proportionally
btcli subnets emission set-value --netuid 12 --slot owner --value 0.10

# nudge one slot up or down
btcli subnets emission increase --netuid 12 --slot miner --by 5%
btcli subnets emission decrease --netuid 12 --slot validator --by 0.02

# write the whole split at once
btcli subnets emission set --netuid 12 --owner 0.10 --validator 0.40 --miner 0.50

Every write validates against the rules locally first and prints each broken rule in the same words the chain error carries, with the allowed range, so a rejected change teaches the constraint. Add --dry-run to preview the plan — the before/after vector, root's share now and after (its baseline), and the resulting effective TAO weight — without signing; add --json for the same as a machine-readable record.

Owners may change the vector once per week per subnet (50,400 blocks). The limit is keyed by subnet, not by owner coldkey, so handing the subnet to a new owner does not reset it; the first change on a subnet is never rate-limited, root is exempt, and dissolving a subnet clears the key so a reused netuid starts fresh. Both owner and root must obey every rule, including the lease floor. Changes take effect on the next block's emission and are announced by the SubnetEmissionWeightsSet event, which carries the full post-merge vector.

Related

• Emissions — the full per-tempo flow
• owner_emission, validator_emission, miner_emission
• set-subnet-emission-weights — the intent
• subnet-emission-weights — the read