Superfluid Staking

Abstract

Superfluid Staking provides the consensus layer more security with a sort of "Proof of Useful Stake". Each person gets an amount of Osmo representative of the value of their share of liquidity pool tokens staked and delegated to validators, resulting in the security guarantee of the consensus layer to also be based on GAMM LP shares. The OSMO token is minted and burned in the context of Superfluid Staking. Throughout all of this, OSMO's supply is preserved in queries to the bank module.

The process

All of the below methods are found under the Superfluid modules.

• The SuperfluidDelegate method stores your share of bonded liquidity pool tokens, with validateLock as a verifier for lockup time.
• GetSuperfluidOsmo mints OSMO tokens each day for delegation as a representative of the value of your pool share. This amount is minted because the staking module at the moment requires staked tokens to be in OSMO. This amount is burned each day and re-minted to keep the representative amount of the value of your pool share accurate. The lockup duration is guaranteed from the underlying lockup module.
• GetExpectedDelegationAmount iterates over each (denom, delegate) pair and checks for how much OSMO we have delegated. The difference from the current balance to what is expected is burned / minted to match with the expected.
• A messageServer method executes the Superfluid delegate message.
• syntheticLockup is used to index bond holders and tracking their addresses for reward distribution or potentially slashing purposes. These track whether if your Superfluid stake is currently bonding or unbonding.
• An IntermediaryAccount is mostly used for the actual reward distribution or slashing events, and are responsible for establishing the connection between each superfluid staked lock and their delegation to the validator. These work by transferring the superfluid OSMO to their respective delegators. Rewards are linearly scaled based on how much you have locked for a given (validator, denom) pair. Rewards are first moved to the incentive gauges, then distributed from the gauges. In this way, we're using the existing gauge reward system for paying out superfluid staking rewards and tracking the amount you have superfluidly staked using the lockup module.
• Rewards are distributed per epoch, which is currently a day. abci.go checks whether or not the current block is at the beginning of the epoch using BeginBlock.
• Superfluid staking will continue to expand to other Osmosis pools based on governance proposals and vote turnouts.

Example

If Alice has 500 GAMM tokens bonded to the ATOM <> OSMO, she will have the equivalent value of OSMO minted, delegated to her chosen staker, and burned for her each day with Superfluid staking. On the user side, all she has to know is who she wants to delegate her tokens to. In order to switch delegation, she has to unbond her tokens from the pool first and then redeposit. Bob, who has a share of the same liquidity pool before Superfluid Staking went live, also has to re-deposit into the pool for the above process to kickstart.

Why mint Osmo? How is this method safe and accurate?

Superfluid staking requires the minting of OSMO because in order to stake on the Osmosis chain, OSMO tokens are required as the chosen collateral. Synthetic Osmo is minted here as a representative of the value of each superfluid staker's liquidity pool tokens.

The pool tokens are acquired by the user from normally staking in a liquidity pool. They get minted an amount of OSMO equivalent to the value of their GAMM pool tokens. This method is accurate because querying the value OSMO every day allows for burning and minting according to the difference in value of OSMO relative to the expected delegation amount (as seen with GetExpectedDelegationAmount). It's like having a price oracle for fairly calculating the amount the user has superfluidly staked.

On epoch (start of every day), we read from the lockup module how much GAMM tokens we have locked which acts as an oracle for the representative price of the GAMM token shares. The superfluid module has "hooks" messages to refresh delegation amounts (RefreshIntermediaryDelegationAmounts) and to increase delegation on lockup (IncreaseSuperfluidDelegation). Then, we see whether or not the superfluid OSMO currently delegated is worth more or less than this expected delegation amount. If the OSMO is worth more, we do instant undelegations and immediately burn the OSMO. If less, we mint OSMO and update the amount delegated. A simplified diagram of this whole process is found below:

This minting is safe because we strict constrain the permissions of Bank (the module that burns and mints OSMO) to do what it's designed to do. The authority is mediated through mintOsmoTokensAndDelegate and forceUndelegateAndBurnOsmoTokens keeper methods called by the SuperfluidDelegate and SuperfluidUndelegate message handlers for the tokens. The hooks above that increase delegation and refresh delegation amounts also call this keeper method.

The delegation is then verified to not already be associated with an intermediary account (to prevent double-staking), and is always delegated or withdrawn taking into account various multipliers for synthetic OSMO value (its worth with respect to the liquidity pool, and a risk modifier) to prevent mint inaccuracies. Before minting, we also check that the message sender is the owner of the locked funds; that the lock is not unlocking; is locked for at least the unbonding period, and is bonded to a single asset. We also check to see if the lock isn't already in superfluid and that the same lock isn't currently being unbonded.

On the end of each epoch, we iterate through all intermediary accounts to withdraw delegation rewards they may have received and put it all into the perpetual gauges corresponding to each account for reward delegation.

Bonding, unbonding, slashing

Here, we describe how token bonding and unbonding works, and what happens to your superfluid tokens in the case of a slashing event.

Bonding

When bonding, your input tokens are locked up and you are given GAMM pool tokens in exchange. These GAMM pool tokens represent a share of the total liquidity pool, and allows you to get transaction fees or participate in external incentive gauge token distributions. When bonding, on top of the regular bonding transaction there will also be a selection of validators. As stated above, OSMO is also minted and burned each day and superfluidly staked to whoever you have chosen to be your validator. You gain additional APR as a reward for bolstering the Osmosis chain's consensus integrity by delegating.

Unbonding

When unbonding, superfluid tokens get un-delegated. After making sure that the unbond message sender is the owner of their corresponding locked funds, the existing synthetic lockup is deleted and replaced with a new synthetic lockup for unbonding purposes. The undelegated OSMO is then instantly withdrawn from the intermediate account and validator using the InstantUndelegate function. The OSMO that was originally used for representing your LP shares are burnt. Moves the tracker for unbonding, allows the underlying lock to start unlocking if desired

Concepts

SyntheticLockups

SyntheticLockups are synthetic forms of PeriodLocks, but different in the sense that they store suffix, which is a combination of bonding/unbonding status + validator address. This is mainly used to track whether an individual lock that has been superfluid staked has an bonding status or an unbonding status from the staking delegations.

Intermediary Account

Intermediary Accounts establish the connections between the superfluid staked locks and delegations to the validator. Intermediary accounts exist for every denom + validator combination, so that it would group locks with the same denom + validator selection. Superfluid staking a lock would mint equivalent amount of OSMO of the lock and send it to the intermediary account and the intermediary accounts would be delegating to the specified validator.

Intermediary Account Connection

Intermediary Accounts Connection serves the role of tracking the locks that an Intermediary Account is dedicated to.

State

Superfluid Asset

A superfluid asset is an alternative asset (non-OSMO) that is allowed by governance to be used for staking.

It can only be updated by governance proposals. We validate at proposal creation time that the denom + pool exists. (Are we going to ignore edge cases around a reference pool getting deleted it)

Intermediary Accounts

Lots of questions to be answered here

Dedicated Gauges

Each intermediary account has a dedicated gauge where it sends the delegation rewards to. Gauges are distributing the rewards to end users at the end of the epoch.

Synthetic Lockups created

At the moment, one lock can only be fully bonded to one validator.

Osmo Equivalent Multipliers

The Osmo Equivalent Multiplier for an asset is the multiplier it has for its value relative to OSMO.

Different types of assets can have different functions for calculating their multiplier. We currently support two asset types.

1. Native Token

The multiplier for OSMO is always 1.

2. Gamm LP Shares

Currently we use the spot price for an asset based on a designated osmo-basepair pool of an asset. The multiplier is set once per epoch, at the beginning of the epoch. In the future, we will switch this out to use a TWAP instead.

State changes

The state of superfluid module state modifiers are classified into below categories.

• Proposals
• Messages
• Epoch
• Hooks

Messages

Superfluid Delegate

Owners of superfluid asset locks can submit MsgSuperfluidDelegate transactions to delegate the Osmo in their locks to a selected validator.

type MsgSuperfluidDelegate struct {
 Sender  string
 LockId  uint64
 ValAddr string
}

State Modifications:

• Safety Checks that are being done before running superfluid logic:
  • Check that Sender is the owner of lock
  • Check that lock corresponds to a single locked asset
  • Check that lock is not unlocking
  • Check that lock is locked for at least the unbonding period
  • Check that this LockID is not already superfluided
  • Check that the same lock isn't being unbonded
• Get the IntermediaryAccount for this lock's Denom and ValAddr pair.
  • Create it + a new gauge for the synthetic denom, if it does not yet exist.
• Create a SyntheticLockup.
• Calculate Osmo to delegate on behalf of this lock, as Osmo Equivalent Multiplier * # LP Shares * Risk Adjustment Factor
  • If this amount is less than 0.000001 Osmo (1 uosmo) reject the transaction, as it would be delegating 0 uosmo
• Mint Osmo to match this amount and send to IntermediaryAccount
• Create a delegation from IntermediaryAccount to Validator
• Create a new perpetual Gauge for distributing staking payouts to locks of a synethic asset based on this Validator / Denom pair.
• Create a connection between this lockID and this IntermediaryAccount

Superfluid Undelegate

type MsgSuperfluidUndelegate struct {
 Sender string
 LockId uint64
}

State Modifications:

• Lookup lock by LockID
• Check that Sender is the owner of lock
• Get the IntermediaryAccount for this lockID
• Delete the SyntheticLockup associated to this lockID + ValAddr pair
• Create a new SyntheticLockup which is unbonding
• Calculate the amount of Osmo delegated on behalf of this lock as Osmo Equivalent Multiplier * # LP Shares * Risk Adjustment Factor
  • If this amount is less than 0.000001 Osmo, there is no delegated Osmo to undelegate and burn
• Use InstantUndelegate to instantly remove delegation from IntermediaryAccount to Validator
• Immediately burn undelegated Osmo
• Delete the connection between lockID and IntermediaryAccount

Lock and Superfluid Delegate

type MsgLockAndSuperfluidDelegate struct {
 Sender string
 Coins sdk.Coins
 ValAddr string
}

This is effectively a multimsg tx of lockup's MsgLockTokens and superfluid's MsgSuperfluidDelegate, but it is implemented as a single msg, because currently we don't have a way of passing the lockid outputted by MsgLockTokens as an input into the MsgSuperfluidDelegate prior to execution.

State Modifications:

• Ensures that Coins has a length of only 1 (we use sdk.Coins instead of sdk.Coin in order to allow more flexibility in the future)
• Creates a lockup with Coins of a lock duration equivalent to the unstaking period from the staking module
  • Uses the lockup module's MsgServer
• Gets the lock id of the created lock, and uses it generate and execute a MsgSuperfluidDelegate message
  • Uses the SuperfluidDelegate function on this msg server

Superfluid Unbond Lock

type MsgSuperfluidUnbondLock struct {
 Sender string
 LockId uint64
}

This message does all the functionality of MsgSuperfluidUndelegate but also starts unbonding the underlying lock as well, allowing both the unstaking and unlocking to complete at the same time. Without using this function, a user will not be able to start unbonding their underlying lock until after the unstaking has finished.

State Modifications:

• This runs the functionality of MsgSuperfluidUndelegate
• It then triggers a force unbond of the underlying lock id

Epochs

Overall Epoch sequence

• Epoch N ends, during AfterEpochEnd:
  • Distribute gauge rewards for all non-superfluid gauges
  • Mint new tokens
    • Issue new Osmo, and send to various modules (distribution, incentives, etc.)
    • 25% currently goes to x/distribution which funds Staking and Superfluid rewards
    • Rewards for Superfluid are based on the just updated delegation amounts, and queued for payout in the next epoch
• BeginBlock for Distribution
  • Distribute staking rewards to all of the 'lazy accounting' accumulators. (F1)
• Epoch N ends, during BeginBlock for superfluid After AfterEpochEnd:
  • Claim staking rewards for every Intermediary Account, put them into gauges.
  • Distribute Superfluid staking rewards from gauges to bonded Synthetic Lock owners
  • Update Osmo Equivalent Multiplier value for each LP token
    • (Currently spot price at epoch)
  • Refresh delegation amounts for all Intermediary Accounts
    • Calculate the expected delegation for this account as Osmo Equivalent Multiplier # LP Shares Risk adjustment
      • If this is less than 0.000001 Osmo it will be rounded to 0
    • Lookup current delegation amount for Intermediary Account
      • If there is no delegation, treat the current delegation as 0
    • If expected amount > current delegation:
      • Mint new Osmo and Delegate to Validator
    • If expected amount < current delegation:
      • Use InstantUndelegate and burn the received Osmo

Staking power updates

We need to be concerned with how/when validators enter and leave the active set.

We expect the guarantee that there is an Intermediary account for every (active validator, superfluid denom) pair, and every (unbonding validator, superfluid denom) pair. (TODO: Where/why)

We also want to avoid resource exhaustion attacks. We relegate concerns around upper-bounding the number of active + unbonding validators to the staking module. This module is liable to potentially cause a 100-1000x amplification factor on this workload.

How we handle it now

• Intermediary accounts are not created on SetSuperfluidAsset
• They are created at-time-of-need on MsgSuperfluidDelegate
• Concerns: What happens if you delegate to an unbonding or jailed validator. Note: Isn't it same as normal delegation for unbonding validator?

Other Module Hooks

-----;

In this section we describe the "hooks" that superfluid module receives from other modules.

AfterEpochEnd

On AfterEpochEnd, we iterate through all existing intermediary accounts and withdraw delegation rewards they have received. Then we send the collective rewards to the perpetual gauge corresponding to the intermediary account. Then we update OSMO backing per share for the specific pool. After the update, iteration through all intermediate accounts happen, undelegating and bonding existing delegations for all superfluid staking and use the updated spot price at epoch time to mint and delegate.

AfterAddTokensToLock

When a token is locked, we first check if the corresponding lock is currently in the state of superfluid delegation. If it is, we run the logic to add delegation via intermediary account.

BeforeValidatorSlashed

Slashes the synthetic lockups and native lockups that is connected to the to be slashed validator.

Proposal Hooks

-----;

In this section we describe the proposals that is associated to superfluid module.

SetSuperfluidAssetsProposal

Enable multiple superfluid assets to be used for superfluid staking.

RemoveSuperfluidAssetsProposal

Disable multiple assets from being used for superfluid staking.

Events

There are 7 types of events that exist in Superfluid module:

• types.TypeEvtSetSuperfluidAsset - "set_superfluid_asset"
• types.TypeEvtRemoveSuperfluidAsset - "remove_superfluid_asset"
• types.TypeEvtSuperfluidDelegate - "superfluid_delegate"
• types.TypeEvtSuperfluidIncreaseDelegation - "superfluid_increase_delegation"
• types.TypeEvtSuperfluidUndelegate - "superfluid_undelegate"
• types.TypeEvtSuperfluidUnbondLock - "superfluid_unbond_lock"
• types.TypeEvtUnpoolId - "unpool_pool_id"

types.TypeEvtSetSuperfluidAsset

This event is emitted in the proposal which set new superfluid asset

It consists of the following attributes:

• types.AttributeDenom
  • The value is the asset denom.
• types.AttributeSuperfluidAssetType
  • The value is the type of asset.

types.TypeEvtRemoveSuperfluidAsset

This event is emitted in the proposal which removes the superfluid asset

It consists of the following attributes:

• types.AttributeDenom
  • The value is the asset denom.

types.TypeEvtSuperfluidDelegate

This event is emitted in the message server after successfully creating a delegation for the given lock ID and the validator to delegate to.

It consists of the following attributes:

• types.AttributeLockId
  • The value is the given lock ID.
• types.AttributeValidator
  • The value is the validator address to delegate to.

types.TypeEvtSuperfluidIncreaseDelegation

This event is emitted in the hook after adding more token to the existing lock

It consists of the following attributes:

• types.AttributeLockId
  • The value is the given lock ID.
• types.AttributeAmount
  • The value is the token amount added to the lock.

types.TypeEvtSuperfluidUndelegate

This event is emitted in the message server after undelegating the currently superfluid delegated position given by lock ID.

It consists of the following attributes:

• types.AttributeLockId
  • The value is the given lock ID.

types.TypeEvtSuperfluidUnbondLock

This event is emitted in the message server after starting unbonding for the currently superfluid undelegating lock.

It consists of the following attributes:

• types.AttributeLockId
  • The value is the given lock ID.

types.TypeEvtUnpoolId

This event is emitted in the message server UnPoolWhitelistedPool

It consists of the following attributes:

• types.AttributeKeySender
  • The value is the msg sender address.
• types.AttributeLockId
  • The value is the pool lpShareDenom.
• types.AttributeNewLockIds
  • The value is the exited lock ids in byte[].

Messages

MsgSuperfluidDelegate

Type	Attribute Key	Attribute Value
superfluid_delegate	lock_id	{lock_id}
superfluid_delegate	validator	{validator}

MsgSuperfluidUndelegate

Type	Attribute Key	Attribute Value
superfluid_undelegate	lock_id	{lock_id}

MsgSuperfluidUnbondLock

Type	Attribute Key	Attribute Value
superfluid_unbond_lock	lock_id	{lock_id}

MsgLockAndSuperfluidDelegate

Type	Attribute Key	Attribute Value
lock_tokens	period_lock_id	{periodLockID}
lock_tokens	owner	{owner}
lock_tokens	amount	{amount}
lock_tokens	duration	{duration}
lock_tokens	unlock_time	{unlockTime}
message	action	lock_tokens
message	sender	{owner}
transfer	recipient	{moduleAccount}
transfer	sender	{owner}
transfer	amount	{amount}
superfluid_delegate	lock_id	{lock_id}
superfluid_delegate	validator	{validator}

Proposals

SetSuperfluidAssetsProposal

Type	Attribute Key	Attribute Value
set_superfluid_asset	denom	{denom}
set_superfluid_asset	superfluid_asset_type	{asset_type}

RemoveSuperfluidAssetsProposal

Type	Attribute Key	Attribute Value
remove_superfluid_asset	denom	{denom}

Queries

Params

message ParamsRequest {};

message ParamsResponse {
  // params defines the parameters of the module.
  Params params = 1 [ (gogoproto.nullable) = false ];
}

message Params {
  sdk.Dec minimum_risk_factor = 1; // serialized as string
}

The params query returns the params for the superfluid module. This currently contains:

• MinimumRiskFactor which is an sdk.Dec that represents the discount to apply to all superfluid staked modules when calculating their staking power. For example, if a specific denom has an OSMO equivalent value of 100 OSMO, but the MinimumRiskFactor param is 0.05, then the denom will only get 95 OSMO worth of staking power when staked.

AssetType

message AssetTypeRequest {
    string denom = 1;
};

message AssetTypeResponse {
    SuperfluidAssetType asset_type = 1;
};

enum SuperfluidAssetType {
  SuperfluidAssetTypeNative = 0;
  SuperfluidAssetTypeLPShare = 1;
}

The AssetType query returns what type of superfluid asset a denom is. AssetTypes are meant for when we support more types of assets for superfluid staking than just LP shares. Each AssetType has a different algorithm used to get its "Osmo equivalent value".

We represent different types of superfluid assets as different enums. Currently, only enum 1 is actually used. Enum value 0 is reserved for the Native staking token for if we deprecate the legacy staking workflow to have native staking also go through the superfluid module. In the future, more enums will be added.

If this query errors, that means that a denom is not allowed to be used for superfluid staking.

AllAssets

message AllAssetsRequest {};

message AllAssetsResponse {
  repeated SuperfluidAsset assets = 1 [ (gogoproto.nullable) = false ];
};

message SuperfluidAsset {
  string denom = 1;
  SuperfluidAssetType asset_type = 2;
}

This parameterless query returns a list of all the superfluid staking compatible assets. The return value includes a list of SuperfluidAssets, which are pairs of denom with SuperfluidAssetType which was described in the previous section.

This query does not currently support pagination, but may in the future.

AssetMultiplier

message AssetMultiplierRequest {
    string denom = 1;
};

message AssetMultiplierResponse {
  OsmoEquivalentMultiplierRecord osmo_equivalent_multiplier = 1;
};

message OsmoEquivalentMultiplierRecord {
  int64 epoch_number = 1;
  string denom = 2;
  string multiplier = 3;
}

This query allows you to find the multiplier factor on a specific denom. The Osmo-Equivalent-Multiplier Record for epoch N refers to the osmo worth we treat a denom as having, for all of epoch N. For now, this is the spot price at the last epoch boundary, and this is reset every epoch. We currently don't store historical multipliers, so the epoch parameter is kind of meaningless for now.

To calculate the staking power of the denom, one needs to multiply the amount of the denom with OsmoEquivalentMultipler from this query with the MinimumRiskFactor from the Params query endpoint.

staking_power = amount * OsmoEquivalentMultipler * MinimumRiskFactor

ConnectedIntermediaryAccount

message ConnectedIntermediaryAccountRequest {
  uint64 lock_id = 1;
}

message ConnectedIntermediaryAccountResponse {
  SuperfluidIntermediaryAccountInfo account = 1;
}

message SuperfluidIntermediaryAccount {
  string denom = 1;
  string val_addr = 2;
  uint64 gauge_id = 3; // perpetual gauge for rewards distribution
}

Every superfluid denom and validator pair has an associated "intermediary account", which does the actual delegation. This query helps find the superfluid intermediary account for any superfluid position.

That lock_id parameter passed in is the underlying lock id for the superfluid, NOT the synthetic lock id.

This query can be used to find the validator a superfluid lock is delegated to. The gauge_id also refers to the perpetual gauge that is used to pay out the superfluid positions associated with this intermediary account.

AllIntermediaryAccounts

message AllIntermediaryAccountsRequest {
  cosmos.base.query.v1beta1.PageRequest pagination = 1;
};

message AllIntermediaryAccountsResponse {
  repeated SuperfluidIntermediaryAccountInfo accounts = 1;
  cosmos.base.query.v1beta1.PageResponse pagination = 2;
};

This query returns a list of all superfluid intermediary accounts. It supports pagination.

SuperfluidDelegationAmount

message SuperfluidDelegationAmountRequest {
  string delegator_address = 1;
  string validator_address = 2;
  string denom = 3;
}

message SuperfluidDelegationAmountResponse {
  repeated cosmos.base.v1beta1.Coin amount = 1 [];
}

This query returns the amount of underlying denom (i.e. lp share) for a triplet of delegator, validator, and denom.

SuperfluidDelegationsByDelegator

message SuperfluidDelegationsByDelegatorRequest {
  string delegator_address = 1;
}

message SuperfluidDelegationsByDelegatorResponse {
  repeated SuperfluidDelegationRecord superfluid_delegation_records = 1;
  repeated cosmos.base.v1beta1.Coin total_delegated_coins = 2;
}

message SuperfluidDelegationRecord {
  string delegator_address = 1;
  string validator_address = 2;
  cosmos.base.v1beta1.Coin delegation_amount = 3;
}

This query returns a list of all the superfluid delegations of a specific delegator. The return value includes, the validator delegated to and the delegated coins (both denom and amount).

The return value of the query also includes the total_delegated_coins which is the sum of all the delegations of that validator.

This query does require iteration that is linear with the number of delegations a delegator has made, but for now until we support many superfluid denoms, should be relatively bounded. Once that increases, we will need to support pagination.

SuperfluidDelegationsByValidatorDenom

message SuperfluidDelegationsByValidatorDenomRequest {
  string validator_address = 1;
  string denom = 2;
}

message SuperfluidDelegationsByValidatorDenomResponse {
  repeated SuperfluidDelegationRecord superfluid_delegation_records = 1;
}

This query returns a list of all superfluid delegations that are with a validator / superfluid denom pair. This query requires a lot of iteration and should be used sparingly. We will need to add pagination to make this usable.

EstimateSuperfluidDelegatedAmountByValidatorDenom

message EstimateSuperfluidDelegatedAmountByValidatorDenomRequest {
  string validator_address = 1;
  string denom = 2;
}

message EstimateSuperfluidDelegatedAmountByValidatorDenomResponse {
  repeated cosmos.base.v1beta1.Coin total_delegated_coins = 1;
}

This query returns the total amount of delegated coins for a validator / superfluid denom pair. This query does NOT involve iteration, so should be used instead of the above SuperfluidDelegationsByValidatorDenom whenever possible. It is called an "Estimate" because it can have some slight rounding errors, due to conversions between sdk.Dec and sdk.Int", but for the most part it should be very close to the sum of the results of the previous query.

Parameters

The superfluid module contains the following parameters:

Key	Type	Example
minimum_risk_factor	decimal	0.01

Slashing

Slashing works by gathering all accounts who were superfluidly staking and delegated to the violating validator and slashing their underlying lock collateral. The amount of tokens to slash are first calculated then removed from the underlying and synthetic lock. Therefore, it is important to select a reputable or reliable validator as to minimize slashing risks on your tokens. At the moment we are slashing at latest price rather than block height price. All slashed tokens go to the community pool.

We first get a hook from the staking module, marking that a validator is about to be slashed at a slashFactor of f, for an infraction at height h.

The staking module handles slashing every delegation to that validator, which will handle slashing the delegation from every intermediary account. However, it is up to the superfluid module to then:

• Slash every constituent superfluid staking position for this validator.
• Slash every unbonding superfluid staking position to this validator.

We do this by:

• Collect all intermediate accounts to this validator
• For each IA, iterate over every lock to the underlying native denom.
• If the lock has a synthetic lockup, it gets slashed.
• The slash works by calculating the amount of tokens to slash.
• It removes these from the underlying lock and the synthetic lock.
• These coins are moved to the community pool.

Nuances

• Slashed tokens go to the community pool, rather than being burned as in staking.
• We slash every unbonding, rather than just unbondings that started after the infraction height.
• We can "overslash" relative to the staking module. (For a slash factor of 5%, the staking module can often burn <5% of active delegation, but superfluid will always slash 5%)

We slash every unbonding, purely because lockup module tracks things by unbonding start time, whereas staking/slashing tracks things by height we begin unbonding at. Thus we get a problem that we cannot convert between these cleanly. Really there should be a storage of all historical block height <> block times for everything in the unbonding period, but this is not considered a near-term problem.

Correcting overslashing

The overslashing possibility stems from a problem in the SDKs slashing module, that really is a bug there, and superfluid is doing the correct thing. https://github.com/cosmos/cosmos-sdk/issues/1440

Basically, slashes to unbondings and redelegations can lower the amount that gets slashed from live delegations in the staking module today.

It turns out this edge case, where superfluid's intermediate account can have more delegation than expected from its underlying collateral, is already safely handled by the Superfluid refreshing logic.

The refreshing logic checks the total amount of tokens in locks to this denom (Reading from the lockup accumulation store), calculates how many osmo that's worth at the epochs new osmo worth for that asset, and then uses that. Thus this safely handles this edge case, as it uses the new 'live' lockup amount.

Minting

Superfluid module has the ability to arbitrarily mint and burn Osmo through the bank module. This is potentially dangerous so we strictly constrain it's ability to do so. This authority is mediated through the mintOsmoTokensAndDelegate and forceUndelegateAndBurnOsmoTokens keeper methods, which are in turn called by message handlers (SuperfluidDelegate and SuperfluidUndelegate) as well as by hooks on Epoch (RefreshIntermediaryDelegationAmounts) and Lockup (IncreaseSuperfluidDelegation)

Invariant

Each of these mechanisms maintains a local invariant between the amount of Osmo minted and delegated by the IntermediaryAccount, and the quantity of the underlying asset held by locks associated to the account, modified by OsmoEquivalentMultiplier and RiskAdjustment for the underlying asset. Namely that total minted/delegated = GetTotalSyntheticAssetsLocked * GetOsmoEquivalentMultiplier * GetRiskAdjustment

This can be equivalently expressed as GetExpectedDelegationAmount being equal to the actual delegation amount.

Message Handlers

SuperfluidDelegate

In a SuperfluidDelegate transaction, we first verify that this lock is not already associated to an IntermediaryAccount, and then use mintOsmoTokenAndDelegate to properly balance the resulting change in GetExpectedDelegationAmount from the increase in GetTotalSyntheticAssetsLocked. i.e. we mint and delegate: GetOsmoEquivalentMultiplier * GetRiskAdjustment * lock.Coins.Amount new Osmo tokens.

SuperfluidUndelegate

When a user submits a transaction to unlock their asset the invariant is maintained by using forceUndelegateAndBurnOsmoTokens to remove an amount of Osmo equal to lockedCoin.Amount * GetOsmoEquivalentMultiplier * GetRiskAdjustment.

Superfluid Hooks

RefreshIntermediaryDelegationAmounts (AfterEpochEnd Hook)

In the RefreshIntermediaryDelegationAmounts method, calls are made to mintOsmoTokensAndDelegate or forceUndelegateAndBurnOsmoTokens to adjust the real delegation up or down to match GetExpectedDelegationAmount.

IncreaseSuperfluidDelegation (AfterAddTokensToLock Hook)

This is called as a result of a user adding more assets to a lock that has already been associated to an IntermediaryAccount. The invariant is maintained by using mintOsmoTokenAndDelegate to match the amount of new asset locked * GetOsmoEquivalentMultiplier * GetRiskAdjustment for the underlying asset.

SlashLockupsForValidatorSlash (BeforeValidatorSlashed Hook)

During slashing the invariant is likely to be temporarily broken if the referenced validator has any unbonding delegations. These unbonding delegations are slashed first, which means that the amount delegated by the IntermediaryAccount will be slashed by less than the SyntheticLocks held by the account.

See Also

GetTotalSyntheticAssetsLocked

TODO - expand on this Uses lockup accumulator to find total amount of synthetic locks for a given IntermediaryAccount (Superfluid Asset + Validator pair)