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Y0

As explained in Causal AI

y0 is a Python library for representing and manipulating causal graphs, including graphs for counterfactual and parallel-world reasoning.

Y0 is a Python library for graph-based causal identification. It represents probability, intervention, and counterfactual queries so algorithms can determine whether observational or experimental data support a causal conclusion. section 10.0 section 10.1.1

Y0 supports a causal workflow by:

  • Representing queries with domain-specific Python objects such as Probability and Variable. section 10.1.1
  • Applying graph algorithms to assess identification and derive estimands from causal models. section 10.0
  • Producing parallel-world and query-specific counterfactual graphs from directed acyclic graphs. section 11.6.1

Online gaming query

Define engagement and in-game purchases as Y0 variables, then construct a probability query such as P(I) or P(I | E) using the library’s DSL. The same causal hierarchy distinguishes intervention queries from counterfactual questions about what a player’s purchases would have been under different engagement. section 10.1.1 section 10.0

Listing 10.1 Creating a query in y0
!pip install git+https://github.com/y0-causal-inference/y0.git@v0.2.0
from y0.dsl import P, Variable      #1
E = Variable("E")     #2
I = Variable("I")     #2
query = P[E](I)     #3
query      #4

Inspect the minimal Python construction of a Y0 query, including installation, variable declaration, probability notation, and rendered output. section 10.1.1

How Causal AI covers it

How deep it goes
Implements graph-based identification, query construction, and counterfactual transformations without developing identification theory from first principles.
Examples
Uses an online gaming DAG, engagement and purchases variables, probability queries, and rendered LaTeX output.
What it assumes
Assumes causal-graph and causal-hierarchy concepts while introducing their operational representation through Python query objects.
What you can do after
Apply it via Python to encode causal queries and derive graph transformations relevant to identification and counterfactual analysis.
How it connects
Links causal identification with causal graphs, causal hierarchy, graph surgery, parallel-world graphs, and counterfactual graphs.

Related concepts

This explainer was generated by Manning's knowledge graph from the text of Causal AI. The section links point to the parts of the book it draws on.