Glossary
A
Active UID
A UID slot that is considered active within a specific subnet, allowing the associated hotkey to participate as a subnet validator or subnet miner.
See also: Subnet Miners, Subnet Validators
Archive Node
A type of public subtensor node that stores the entire blockchain history, allowing for full data access and querying capabilities.
See also: Subtensor Nodes, Managing Subtensor Connections
Axon
A module in the Bittensor API that uses the FastAPI library to create and run API servers. Axons receive incoming Synapse objects. Typically, an Axon is the entry point advertised by a subnet miner on the Bittensor blockchain, allowing subnet validators to communicate with the miner.
See also: Subnet Miners, Subnet Validators
B
Bicameral Legislature
A two-tier legislative system comprising the Triumvirate and the Senate for proposal approval.
See also: Governance, Senate
Bittensor Wallet
A digital wallet that holds the core ownership in the Bittensor network and serves as the user's identity technology underlying all operations.
See also: Wallets, Working with Keys
Block
A unit of data in the Bittensor blockchain, containing a collection of transactions and a unique identifier (block hash). A single block is processed every 12 seconds in the Bittensor blockchain.
See also: Subtensor API
Burn cost
This refers to the required amount of TAO to be recycled when creating a new subnet, i.e., cost of registering a new subnet.
See also: Burn cost
C
Coldkey
A component of a Bittensor wallet responsible for securely storing funds and performing high-risk operations such as transfers and staking. It is encrypted on the user's device. This is analogous to a private key.
See also: Coldkey-Hotkey Security, Working with Keys
Coldkey-hotkey pair
A combination of two keys, a coldkey for secure storage and high-risk operations, and a hotkey for less secure operations and network interactions.
See also: Coldkey-Hotkey Security, Working with Keys
Commit Reveal
The commit reveal feature is designed to solve the weight-copying problem by giving would-be weight-copiers access only to stale weights. Copying stale weights should result in validators departing from consensus.
See also: Commit Reveal
Consensus Score
The consensus score is calculated as the stake-weighted median of all weights assigned to a specific neuron by validators. This creates a consensus threshold that filters out outlier weights, ensuring that only weights near the median consensus are used in final rank calculations.
See also: Yuma Consensus, Consensus-Based Weights
Mathematical Definition:
For each neuron , the consensus score is calculated as:
Where:
- is the weight assigned by validator to neuron
- is the stake of validator
- is the consensus majority ratio (typically 51%)
- is the stake-weighted median function
Calculation Process:
- Weight collection: Gather all weights assigned to each neuron by validators
- Stake weighting: Apply stake weights to validator opinions
- Median calculation: Find stake-weighted median using κ parameter (typically 51%)
- Threshold establishment: Consensus score becomes clipping threshold for weights
Properties and Interpretation:
- Range: [0, 1] normalized values
- High Consensus: Values close to 1 indicate strong validator agreement
- Low Consensus: Values close to 0 indicate weak validator agreement
- Outlier Detection: Weights below consensus score are clipped to 0
Network Security Properties:
- Anti-Manipulation: Consensus filtering prevents weight manipulation by outliers
- Stake-Weighted: Higher stake validators have more influence in consensus
- Dynamic Threshold: Consensus adapts to changing network conditions
- Majority Rule: κ parameter controls consensus strictness (typically 51%)
Relationship to Other Metrics
Consensus vs Trust:
- Consensus: Stake-weighted median of weights (consensus threshold)
- Trust: Ratio of final rank to pre-rank (consensus alignment impact)
- Relationship: Consensus determines weight clipping, Trust measures the impact
Consensus vs Ranks:
- Consensus: Threshold for weight filtering
- Ranks: Final performance scores after consensus filtering
- Relationship: Consensus influences rank calculation through weight clipping
Consensus vs Validator Trust:
- Consensus: Per-neuron consensus thresholds
- Validator Trust: Sum of clipped weights set by each validator
- Relationship: Validator trust measures validator influence in consensus
Source:
bittensor/bittensor/core/metagraph.py:360-372
subtensor/pallets/subtensor/src/epoch/run_epoch.rs:595
D
Delegate
A subnet validator that receives staked TAO tokens from delegators and performs validation tasks in one or more subnets.
See also: Delegation, Managing Stake with btcli
Delegate Stake
The amount of TAO staked by the delegate themselves.
See also: Managing Stake with btcli, Managing Stake with SDK
Delegation
Also known as staking, delegating TAO to a validator (who is thereby the delegate), increases the validator's stake and secure a validator permit.
See also: Delegation, Managing Stake with btcli
Dendrite
A client instance used by subnet validators and subnet miners to transmit information to axons on subnet miners and subnet validators. Dendrites communicate with axons using the server-client (Axon-dendrite) protocol.
See also: Subnet Miners, Subnet Validators
Deregistration
The process of removing a subnet miner or a subnet validator from the subnet due to poor performance.
See also: Miner Deregistration, Subnet Miners
E
EdDSA Cryptographic Keypairs
A cryptographic algorithm used to generate public and private key pairs for coldkeys and hotkeys in the Bittensor wallet.
See also: Working with Keys, Coldkey-Hotkey Security
Effective stake
The total staked TAO amount of a delegate, including their own TAO tokens and those delegated by nominators.
See also: Managing Stake with btcli, Managing Stake with SDK
Emission
Every block, currency is injected into each subnet in Bittensor, and every tempo (or 360 blocks), it is extracted by participants (miners, validators, stakers, and subnet creators).
Emission is this process of generating and allocating currency to participants. The amount allocated to a given participant over some duration of time is also often referred to as 'their emissions' for the period.
Emissions are protected from manipulation through Exponential Moving Average (EMA) mechanisms that smooth both validator-miner bond evolution and subnet price effects.
See also: Emissions, Exponential Moving Average (EMA)
Encrypting the Hotkey
An optional security measure for the hotkey.
See also: Coldkey-Hotkey Security, Working with Keys
Exponential Moving Average (EMA)
A weighted moving average that prioritizes recent observations while exponentially decreasing the weight of older data points. In Bittensor, EMA is used in two critical stability mechanisms:
-
Validator-Miner Bond Smoothing: Smooths the evolution of bonds between validators and miners over time, rewarding early discovery while preventing abrupt manipulation attempts. Has two modes:
- Basic Mode: Single α ≈ 0.1 (~7-22 blocks for significant changes)
- Liquid Alpha Mode: Dynamic α range 0.7-0.9 based on consensus alignment (~1-13 blocks depending on consensus)
-
Subnet Price Emission Smoothing: Protects emissions from price manipulation by extremely slowly incorporating price changes into emission calculations (α ≈ 0.000003, ~30 days for 50% adjustment)
Formula: EMA(t) = α × Current_Value + (1 - α) × EMA(t-1)
Key Properties:
- Lower α = slower adaptation, higher stability
- Higher α = faster adaptation, lower stability
- Bittensor prioritizes stability with conservative α values
See also: Understanding Exponential Moving Averages, Consensus-based Weights, Validator-Miner Bonds, Emission
External Wallet
A Bittensor wallet created through the Bittensor website or using a tool like subkey, allowing users to use TAO without installing Bittensor.
See also: Wallets, Installation
F
Fast blocks
A development-only configuration that accelerates block production to 250ms intervals, enabling rapid local testing and immediate execution of on-chain operations.
See also: Create a local instance
H
Hotkey
A component of a Bittensor wallet responsible for less secure operations such as signing messages into the network, secure a UID slot in a subnet, running subnet miners and subnet validators in a subnet. It can be encrypted or unencrypted, but is unencrypted by default. The terms "account" and "hotkey" are used synonymously.
See also: Coldkey-Hotkey Security, Working with Keys
Hotkey-Coldkey Pair
Authentication mechanism for delegates and nominators and for delegates participating in the Senate.
See also: Coldkey-Hotkey Security, Working with Keys
I
Immunity Period
A grace period granted to newly registered neurons during which they are protected from deregistration due to poor performance. The immunity period allows new miners and validators time to establish themselves and improve their performance before becoming eligible for pruning. The default period being is 4096 blocks (~13.7 hours), but can be configured by the subnet creator.
See also: Miner Deregistration, Validator Deregistration, Subnet Hyperparameters
Incentives
A portion of the TAO emission received by the subnet miners when they provide valuable services and compete for UID slots in a subnet.
See also: Emissions, Anatomy of Incentive Mechanism
Incentive Mechanism
A system that drives the behavior of subnet miners and governs consensus among subnet validators in a Bittensor subnet. Each subnet has its own incentive mechanism, which should be designed carefully to promote desired behaviors and penalize undesired ones.
See also: Anatomy of Incentive Mechanism, Understanding Subnets
Issuance
The total amount of TAO circulating in the Bittensor network. Includes TAO that is help in wallets and subnet liquidity pools, as well as TAO that is locked as subnet registration fees.
This can be viewed on Bittensor explorers such as TAO.app and TAOstats.
To query it directly from the change, see: Subtensor Storage Query Example: Total Issuance
See also: Recycling, burning, and locking
L
Lite Node
A type of public subtensor node that stores limited blockchain data and relies on archive nodes for full historical data.
See also: Subtensor Nodes, Managing Subtensor Connections
Local Blockchain
A private blockchain used for developing and testing subnet incentive mechanisms. A local blockchain is not public and is isolated from any Bittensor network.
See also: Local Build, Create a Subnet
Local Wallet
A Bittensor wallet created on the user's machine, requiring the installation of Bittensor.
See also: Wallets, Installation
Loss Function
In the context of machine learning, a mathematical function that measures the difference between the predicted output and the ground truth. In Bittensor, incentive mechanisms act as loss functions that steer subnet miners towards desirable outcomes.
See also: Anatomy of Incentive Mechanism, Understanding Subnets
M
Mainchain
The primary Bittensor blockchain network, used for production purposes and connected to lite or archive nodes.
See also: Bittensor Networks, Subtensor Nodes