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z3/.github/skills/simplify/SKILL.md
Angelica Moreira 9d674404c8 Add action/expectation/result structure to all skill definitions
Each step in every SKILL.md now carries labeled Action, Expectation,
and Result blocks so the agent can mechanically execute, verify, and
branch at each stage. Format chosen after comparing three variants
(indented blocks, inline keywords, tables) on a prove-validity
simulation; indented blocks scored highest on routing completeness
and checkability.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-03-11 19:51:59 +00:00

2.8 KiB

name description
simplify Reduce formula complexity using Z3 tactic chains. Supports configurable tactic pipelines for boolean, arithmetic, and bitvector simplification.

Given a formula, apply a sequence of Z3 tactics to produce an equivalent but simpler form. This is useful for understanding what Z3 sees after preprocessing, debugging tactic selection, and reducing formula size before solving.

Step 1: Choose tactics

Action: Select a tactic chain from the available Z3 tactics based on the formula's theory.

Expectation: A comma-separated list of tactic names suitable for the formula domain.

Result: If unsure, use the default chain: simplify,propagate-values,ctx-simplify. For bitvector formulas, add bit-blast. Proceed to Step 2.

Tactic What it does
simplify constant folding, algebraic identities
propagate-values substitute known equalities
ctx-simplify context-dependent simplification
elim-uncnstr remove unconstrained variables
solve-eqs Gaussian elimination
bit-blast reduce bitvectors to booleans
tseitin-cnf convert to CNF
aig and-inverter graph reduction

Step 2: Run simplification

Action: Invoke simplify.py with the formula and optional tactic chain.

Expectation: The script applies each tactic in sequence and prints the simplified formula. A run entry is logged to z3agent.db.

Result: If the output is simpler, pass it to solve or prove. If unchanged, try a different tactic chain.

python3 scripts/simplify.py --formula "(assert (and (> x 0) (> x 0)))" --vars "x:Int"
python3 scripts/simplify.py --file formula.smt2 --tactics "simplify,propagate-values,ctx-simplify"
python3 scripts/simplify.py --file formula.smt2 --debug

Without --tactics, the script applies the default chain: simplify, propagate-values, ctx-simplify.

Step 3: Interpret the output

Action: Read the simplified formula output in SMT-LIB2 syntax.

Expectation: One or more (assert ...) blocks representing equivalent subgoals.

Result: A smaller formula indicates successful reduction. Pass the result to solve, prove, or optimize as needed.

Parameters

Parameter Type Required Default Description
formula string no SMT-LIB2 formula to simplify
vars string no variable declarations as "name:sort" pairs
file path no path to .smt2 file
tactics string no simplify,propagate-values,ctx-simplify comma-separated tactic names
timeout int no 30 seconds
z3 path no auto path to z3 binary
debug flag no off verbose tracing
db path no .z3-agent/z3agent.db logging database