Concepts

Emission weights

How a subnet owner divides alpha emission between owner, validators and miners, and how root TAO stakers are paid their baseline share off the top of the validator slot every block.

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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, and the five slots sum to exactly one with the subnet's gamma shares. 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

SlotNamePaid tov1 rule
0burnnothing — alpha is destroyed (still counts toward issuance)with recycle, ≤ 0.33 combined
1recyclenothing — alpha leaves SubnetAlphaOut and TotalAlphaIssuancewith burn, ≤ 0.33 combined
2ownerthe subnet owner's hotkey at each epoch0 ≤ owner ≤ 0.33; lease-created subnets ≥ 0.18
3validatorroot's baseline share first, then alpha validator dividendsvalidator ≤ 0.50, and strictly above root's baseline share
4minerminer incentive, split across the subnet's mechanismsminer ≥ 0.33

The owner slot at zero means "no owner cut"; the legacy owner_cut_enabled hyperparameter is now simply owner > 0. Burn and recycle share a combined 33% cap (BurnRecycleEmissionAboveMaximum).

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 TAO stakers are paid out of the validator bucket first; shrinking the validator slot would, on its own, shrink what they receive. The rule below prevents that.

Root off the top

Root TAO is weighted against alpha by the global TAO weight w (TaoWeight, 0.18 on mainnet today). Before emission weights existed, each block's alpha to root stakers from a subnet was

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

with V the fixed 41% validator slot and A the subnet's alpha issuance.

That payout is kept and detached from the owner's choice of V. Every block, for every subnet, the chain computes root's baseline share

r = V0 × x / (x + A)        with x = root_tao × TaoWeight

where V0 is the validator share of the default vector (0.41 on mainnet, derived from the default owner cut — a single global constant) — what root would earn from this subnet right now if the owner had never touched the vector. Root is paid min(V, r) × alpha_out off the top of the validator slot and alpha validators share the rest, (V − min(V, r)) × alpha_out (get_root_emission_share in emission_weights.rs, applied in run_coinbase.rs). The owner and miner slots are untouched.

Because r is recomputed from live state every block, root's payout tracks the baseline continuously — as issuance grows against root TAO, as root stake moves, or as governance changes TaoWeight — with no call from anyone. An owner lowering V from 41% to 20% takes the whole 21 points from alpha validators; root's slice is identical before and after, and no sequence of changes can ratchet it in either direction. There is no per-subnet TAO weight: stake weighting inside Yuma Consensus, the TAO-vs-alpha split of validator dividends, child/parent stake and the pool side all use the global TaoWeight exactly as before.

A set call fails with ValidatorEmissionTooLowToPreserveRoot when V_new ≤ r: root would take the entire slot and alpha validators would get nothing, so the floor at this block is r itself. On a mainnet subnet with 5.4M TAO on root, 6.5M alpha issued and TaoWeight = 0.18, r is about 5.40% of emission and the validator share can go down to anything strictly above that. The floor moves with root stake, issuance and the global weight, so btcli subnets emission show prints the current value. With no root stake there is nothing to preserve and any positive V is accepted.

The check runs at set time while the baseline keeps moving. If r later grows past a subnet's V, root's cut is capped at the whole validator slot (V × alpha_out) and alpha validators receive nothing until the owner raises V; root is never paid more than the slot. show reports this as capped, and the runtime API returns both root_baseline_share (r) and root_share (min(V, r)).

The pool side is unchanged. 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 and the gamma shares 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 what alpha validators keep — 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.

Gamma shares

A subnet can also pay shares of its emission into other subnets' gamma. Each gamma share names a target subnet and takes at most 10% of alpha_out, and a subnet has at most 16. A subnet with a 10% gamma share has five slots summing to 90%.

The subnet owner (or root) sets the whole split, the five slots and the gamma shares, with

AdminUtils.sudo_set_subnet_emission_weights_v2(netuid: u16, split: Vec<(EmissionSlot, u64)>)

where EmissionSlot is Burn, Recycle, Owner, Validator, Miner or Gamma { netuid }. The split lists each slot at most once, in that order and gamma slots by netuid (EmissionSlotsNotAscending), and a slot it leaves out is zero. The call has the rules, rate limit and freeze window of set-subnet-emission-weights. A gamma share must name another subnet, with gamma enabled, that root has whitelisted for gamma emission with AdminUtils.sudo_set_subnet_gamma_emission_whitelisted(netuid, whitelisted) (InvalidValue, GammaDisabled, GammaEmissionTargetNotWhitelisted, GammaEmissionAboveMaximum, TooManyGammaShares). A subnet under a lease has no gamma shares (GammaEmissionNotSettableOnLeasedSubnet).

The gamma shares of each block's alpha_out accrue together and are allotted to their targets at the subnet's epoch. Each target then converts on its own: the subnet sells the alpha down to 2% below the higher of its fast moving and spot prices, buys the target's alpha with all of the TAO up to 2% above the lower of the target's two, and burns it. The gamma, valued as a mint values it, is credited to the subnet owner's deposit at the subnet owner hotkey on the target, which opens with the target's default spender and no daily spend cap, and GammaEmissionMinted reports it. Alpha the pools cannot take in one conversion waits for the next epoch, and so does all of it while a price is past its bound, the subnet's subtoken is disabled, gamma cannot be minted on the target, the TAO/USD price is stale, the gamma would be below 0.1 or the subnet owner coldkey does not own the owner hotkey.

A target that leaves the whitelist or is dissolved is removed from every split: its share is added to the miner slot and its unconverted alpha to the pending miner emission, as is the unconverted alpha of a share the owner drops. The v2 call and every removal emit SubnetEmissionWeightsSet with the five slots and SubnetGammaEmissionSet with the gamma shares, and btcli subnets emission show --json reports their sum as gamma_share.