Discount eligibility rule: (student OR senior) AND NOT expired AND (member OR coupon)
A five-input discount rule, (student OR senior) AND NOT expired AND (member OR coupon): a 32-row table with nine qualifying rows, a four-term DNF, 7 NOR gates against 31 NAND, and no Karnaugh map because five inputs exceed the four-variable limit.
The glossary fixes the inputs: student means a student card, senior means 65 or older, expired means the card or coupon has expired, member means membership, coupon means a coupon is presented. The rule is three requirements ANDed together: some status, nothing expired, some proof of entitlement. The engine's reading lists exactly those three. With five inputs the table has 32 rows, and the output is true on nine of them, Σm(9, 10, 11, 17, 18, 19, 25, 26, 27).
The checks: not a tautology, counterexample all five inputs FALSE; satisfiable, witness student = FALSE, senior = TRUE, expired = FALSE, member = FALSE, coupon = TRUE, a senior with a coupon. The simplifier found no law that shortens the five-operator rule, and the CNF converter returns it unchanged as three clauses. The DNF converter applies distribution twice and expands it into four terms of three literals, one per combination of status and entitlement. The gate counts are lopsided, 7 NOR against 31 NAND. The Karnaugh map is not available: the engine's map handles up to four variables and this rule has five.
Eligibility rules of this shape, several OR-groups under one AND, are the common case in pricing and benefits logic, and the DNF is the list of concrete customer profiles that qualify, which is also the list of positive test cases. The thing to watch is expired: it is a single blocker that applies to both the status and the entitlement, and the glossary wording, “the card or coupon”, leaves open which document it refers to. A rule with one expired flag for two documents is a modelling choice worth making explicit.
student: the customer has a student card; senior: the customer is 65 or older; expired: the card or coupon has expired; member: the customer is a member; coupon: the customer presents a coupon;
discount := (student OR senior) AND NOT expired AND (member OR coupon) · output
Exact checks
Truth table (32 rows)
| # | student | senior | expired | member | coupon | discount |
|---|---|---|---|---|---|---|
| 0 | FALSE | FALSE | FALSE | FALSE | FALSE | FALSE |
| 1 | FALSE | FALSE | FALSE | FALSE | TRUE | FALSE |
| 2 | FALSE | FALSE | FALSE | TRUE | FALSE | FALSE |
| 3 | FALSE | FALSE | FALSE | TRUE | TRUE | FALSE |
| 4 | FALSE | FALSE | TRUE | FALSE | FALSE | FALSE |
| 5 | FALSE | FALSE | TRUE | FALSE | TRUE | FALSE |
| 6 | FALSE | FALSE | TRUE | TRUE | FALSE | FALSE |
| 7 | FALSE | FALSE | TRUE | TRUE | TRUE | FALSE |
| 8 | FALSE | TRUE | FALSE | FALSE | FALSE | FALSE |
| 9 | FALSE | TRUE | FALSE | FALSE | TRUE | TRUE |
| 10 | FALSE | TRUE | FALSE | TRUE | FALSE | TRUE |
| 11 | FALSE | TRUE | FALSE | TRUE | TRUE | TRUE |
| 12 | FALSE | TRUE | TRUE | FALSE | FALSE | FALSE |
| 13 | FALSE | TRUE | TRUE | FALSE | TRUE | FALSE |
| 14 | FALSE | TRUE | TRUE | TRUE | FALSE | FALSE |
| 15 | FALSE | TRUE | TRUE | TRUE | TRUE | FALSE |
| 16 | TRUE | FALSE | FALSE | FALSE | FALSE | FALSE |
| 17 | TRUE | FALSE | FALSE | FALSE | TRUE | TRUE |
| 18 | TRUE | FALSE | FALSE | TRUE | FALSE | TRUE |
| 19 | TRUE | FALSE | FALSE | TRUE | TRUE | TRUE |
| 20 | TRUE | FALSE | TRUE | FALSE | FALSE | FALSE |
| 21 | TRUE | FALSE | TRUE | FALSE | TRUE | FALSE |
| 22 | TRUE | FALSE | TRUE | TRUE | FALSE | FALSE |
| 23 | TRUE | FALSE | TRUE | TRUE | TRUE | FALSE |
| 24 | TRUE | TRUE | FALSE | FALSE | FALSE | FALSE |
| 25 | TRUE | TRUE | FALSE | FALSE | TRUE | TRUE |
| 26 | TRUE | TRUE | FALSE | TRUE | FALSE | TRUE |
| 27 | TRUE | TRUE | FALSE | TRUE | TRUE | TRUE |
| 28 | TRUE | TRUE | TRUE | FALSE | FALSE | FALSE |
| 29 | TRUE | TRUE | TRUE | FALSE | TRUE | FALSE |
| 30 | TRUE | TRUE | TRUE | TRUE | FALSE | FALSE |
| 31 | TRUE | TRUE | TRUE | TRUE | TRUE | FALSE |
Plain-language reading
Beginnerdiscount is true exactly when all of the following hold:
1. at least one of student or senior is true (both may be true)
2. expired is false
3. at least one of member or coupon is true (both may be true)
In every other case, discount is false.
About the operators:
- AND is true only when all of its parts are true.
- OR is inclusive: it is true when at least one part is true, including when several are.
- NOT reverses a value: true becomes false and false becomes true.
Intermediatediscount is true exactly when all of the following hold:
1. at least one of student or senior is true (both may be true)
2. expired is false
3. at least one of member or coupon is true (both may be true)
In every other case, discount is false.
Advanceddiscount is true exactly when all of the following hold [conjunction ∧]:
1. at least one of student or senior is true (both may be true) [inclusive disjunction ∨]
2. expired is false [negation ¬]
3. at least one of member or coupon is true (both may be true) [inclusive disjunction ∨]
In every other case, discount is false.
Formal notation: (student ∨ senior) ∧ ¬expired ∧ (member ∨ coupon)
Logic diagram
Simplification, step by step
The engine found no law that shortens this expression; it is already as short as its rewriting laws can make it.
(student OR senior) AND NOT expired AND (member OR coupon)
Karnaugh map
A Karnaugh map shows at most 4 variables; this expression has more. Use the tool to fix some inputs and view a labelled slice. discount depends on 5 inputs that are not shown to be irrelevant; a Karnaugh map shows at most 4. Fix coupon to view an explicitly labelled slice.
Minterms and maxterms
discount(student, senior, expired, member, coupon) = Σm(9, 10, 11, 17, 18, 19, 25, 26, 27)discount(student, senior, expired, member, coupon) = ΠM(0, 1, 2, 3, 4, 5, 6, 7, 8, 12, 13, 14, 15, 16, 20, 21, 22, 23, 24, 28, 29, 30, 31)Variable order: student, senior, expired, member, coupon · 32 rows
Normal forms
Conjunctive normal form (CNF)
(student OR senior) AND NOT expired AND (member OR coupon)3 clauses, 5 literals · complete
Disjunctive normal form (DNF)
(student AND NOT expired AND member) OR (student AND NOT expired AND coupon) OR (senior AND NOT expired AND member) OR (senior AND NOT expired AND coupon)4 terms, 12 literals · complete · Distribution ×2
NAND-only and NOR-only
NAND-only form
NAND(NAND(NAND(NAND(NAND(NAND(student, student), NAND(senior, senior)), NAND(expired, expired)), NAND(NAND(NAND(student, student), NAND(senior, senior)), NAND(expired, expired))), NAND(NAND(member, member), NAND(coupon, coupon))), NAND(NAND(NAND(NAND(NAND(student, student), NAND(senior, senior)), NAND(expired, expired)), NAND(NAND(NAND(student, student), NAND(senior, senior)), NAND(expired, expired))), NAND(NAND(member, member), NAND(coupon, coupon))))31 gates · verified equivalent on every row
NOR-only form
NOR(NOR(NOR(NOR(student, senior), expired), NOR(NOR(student, senior), expired)), NOR(member, coupon))7 gates · verified equivalent on every row
The same rule as code
Python
# -*- coding: utf-8 -*-
# Generated by Tangibool (tangibool.python/1). Do not edit by hand; regenerate from the source revision.
# Model: not stated
# Source revision: reference
# Interpretation status: not stated
"""Tangibool evaluator (decision model).
Generated deterministically from the validated Boolean model; it evaluates exactly that
model. It does not establish that the model is a complete, legal, or safe statement of a
real-world rule, and evaluating examples does not verify the rule.
Source revision: reference
Interpretation status: not stated
Exporter: 1.0.0 (format tangibool.python/1; engine 1.0.0; semantics tangibool-semantics/1)
Logic digest: a7ccaac3652524d0b2342e0bc0961ef98c69958628e3ef40fb5cadf1fd7ebdd8
Assumptions digest: d58ee1ad38e23e5093e4baa1047b5ae70d6972e08f555e34ac3fa16df63c4a78
Inputs (dict keys, declared order) and generated parameter names:
'student' -> input_student
'senior' -> input_senior
'expired' -> input_expired
'member' -> input_member
'coupon' -> input_coupon
Outputs (declared order) and their functions:
'discount' -> output_discount(inputs)
Assumptions (the declared scope, checked by in_scope(inputs)):
none; every complete assignment is in scope.
Input contract:
Every required input must be exactly True or False (type(value) is bool). Missing
inputs, None, strings, integers (including 0 and 1), and keys that are not declared
inputs raise InputError before anything is evaluated, including inputs that a
short-circuiting operator would never read. Results are always bool.
Scope:
Decision functions raise OutOfScopeError when the inputs violate an assumption; an
out-of-scope assignment is never turned into a False result. Pass check_scope=False
to evaluate without the scope check, and use in_scope(inputs) to test it separately.
Usage:
import tangibool_model as model
model.evaluate({'student': False, 'senior': False, 'expired': False, 'member': False, 'coupon': False})
# -> {'discount': False}
model.output_discount({'student': False, 'senior': False, 'expired': False, 'member': False, 'coupon': False})
# -> False
model.evaluate({'student': 1, 'senior': False, 'expired': False, 'member': False, 'coupon': False})
# raises InputError: 1 is an int, not a bool
"""
import collections.abc as _abc
from typing import Dict, Mapping, Tuple
__all__ = [
"MODEL_INFO",
"IDENTIFIER_MAP",
"INPUT_NAMES",
"OUTPUT_NAMES",
"ASSUMPTIONS",
"InputError",
"OutOfScopeError",
"minterm_index",
"in_scope",
"evaluate",
"output_discount",
]
MODEL_INFO = {
"format": "tangibool.python/1",
"mode": "decision",
"model": None,
"revision": "reference",
"interpretation": None,
"exporter": "1.0.0",
"engine_version": "1.0.0",
"semantics_version": "tangibool-semantics/1",
"logic_digest": "a7ccaac3652524d0b2342e0bc0961ef98c69958628e3ef40fb5cadf1fd7ebdd8",
"assumptions_digest": "d58ee1ad38e23e5093e4baa1047b5ae70d6972e08f555e34ac3fa16df63c4a78",
"primary_output": "discount",
"unused_inputs": (),
"subcircuits": (),
}
# Stable ID -> generated identifier (reversible mapping; names are exact, escaped strings).
IDENTIFIER_MAP = {
"v_97a451a60f14": {"kind": "input", "name": "student", "identifier": "input_student"},
"v_9373a966ab63": {"kind": "input", "name": "senior", "identifier": "input_senior"},
"v_7a1672e8b8cb": {"kind": "input", "name": "expired", "identifier": "input_expired"},
"v_dbfd54032935": {"kind": "input", "name": "member", "identifier": "input_member"},
"v_67d46adf341f": {"kind": "input", "name": "coupon", "identifier": "input_coupon"},
"f_8a13877dfb35": {"kind": "output", "name": "discount", "identifier": "output_discount"},
}
INPUT_NAMES = ("student", "senior", "expired", "member", "coupon")
OUTPUT_NAMES = ("discount",)
ASSUMPTIONS = ()
_DECLARED_INPUTS = frozenset(INPUT_NAMES)
_SCOPE_INPUTS = ()
_ASSUMPTION_FORMULAS = {entry["name"]: entry["formula"] for entry in ASSUMPTIONS}
class InputError(ValueError):
"""Raised when inputs are missing, undeclared, or not exactly True/False.
Every required input must satisfy type(value) is bool. Missing inputs, None, strings,
integers (including 0 and 1), and keys that are not declared inputs are rejected before
anything is evaluated. A missing input is never treated as False. The individual problems
are listed in the problems attribute.
"""
def __init__(self, problems):
self.problems = tuple(problems)
super().__init__("Invalid inputs: " + "; ".join(self.problems))
class OutOfScopeError(ValueError):
"""Raised when the inputs violate the model's assumptions (its declared scope).
Outside its assumptions the rule has no decision: this error is never a False result.
The names of the violated assumptions are in the violated attribute.
"""
def __init__(self, violated):
self.violated = tuple(violated)
details = ", ".join(name + " (" + _ASSUMPTION_FORMULAS.get(name, "?") + ")" for name in self.violated)
super().__init__(
"Out of scope: the inputs violate "
+ ("assumption " if len(self.violated) == 1 else "assumptions ")
+ details
+ ". The rule has no decision outside its assumptions; this is not a False result."
)
def _short_repr(value: object) -> str:
text = repr(value)
return text if len(text) <= 60 else text[:57] + "..."
def _checked_inputs(inputs: Mapping[str, bool], required: Tuple[str, ...], check_scope: bool) -> Dict[str, bool]:
"""Validate inputs strictly before anything is evaluated and return a plain copy."""
if type(check_scope) is not bool:
raise TypeError("check_scope must be True or False")
if not isinstance(inputs, _abc.Mapping):
raise InputError(["inputs must be a mapping from input names to True/False, got " + type(inputs).__name__])
problems = []
for key in inputs:
if type(key) is not str or key not in _DECLARED_INPUTS:
declared = ", ".join(repr(name) for name in INPUT_NAMES) or "none"
problems.append("undeclared input " + _short_repr(key) + " (declared inputs: " + declared + ")")
needed = tuple(required) + (_SCOPE_INPUTS if check_scope else ())
for name in needed:
if name not in inputs:
problems.append("missing required input " + repr(name))
for key, value in inputs.items():
if type(key) is str and key in _DECLARED_INPUTS and type(value) is not bool:
problems.append(
"input " + repr(key) + " must be True or False (type bool), got "
+ type(value).__name__ + " " + _short_repr(value)
)
if problems:
raise InputError(list(dict.fromkeys(problems)))
return dict(inputs.items())
def _require_bool_args(function: str, pairs: Tuple[Tuple[str, object], ...]) -> None:
problems = [
"argument " + repr(name) + " of " + function + " must be True or False (type bool), got "
+ type(value).__name__ + " " + _short_repr(value)
for name, value in pairs
if type(value) is not bool
]
if problems:
raise InputError(problems)
def minterm_index(*values: bool) -> int:
"""Row index of an assignment over a declared variable order.
The first value is the most significant bit, so all-False is row 0. Used for indexed
minterm (sum) and maxterm (product) forms.
"""
index = 0
for value in values:
if type(value) is not bool:
raise InputError(["minterm_index() takes True/False values, got " + type(value).__name__ + " " + _short_repr(value)])
index = index * 2 + (1 if value else 0)
return index
def _scope_values(values: Dict[str, bool]) -> Tuple[Tuple[str, bool], ...]:
"""Value of every enabled, confirmed assumption for validated inputs, in declared order."""
return ()
def _require_in_scope(values: Dict[str, bool]) -> None:
violated = tuple(name for name, holds in _scope_values(values) if not holds)
if violated:
raise OutOfScopeError(violated)
def in_scope(inputs: Mapping[str, bool]) -> bool:
"""True when the inputs satisfy every assumption (the model's declared scope).
Requires the inputs the assumptions read; raises InputError for invalid inputs.
"""
values = _checked_inputs(inputs, (), True)
return all(holds for _, holds in _scope_values(values))
# ---- Formula bodies (inputs are validated by the public functions below) ----
def _compute_output_discount(input_student: bool, input_senior: bool, input_expired: bool, input_member: bool, input_coupon: bool) -> bool:
"""Decision output 'discount': (student OR senior) AND NOT expired AND (member OR coupon)"""
return (input_student or input_senior) and (not input_expired) and (input_member or input_coupon)
# ---- Public API ----
def output_discount(inputs: Mapping[str, bool], *, check_scope: bool = True) -> bool:
"""Decision output 'discount' (stable ID f_8a13877dfb35).
'discount' := (student OR senior) AND NOT expired AND (member OR coupon)
Required inputs: 'student', 'senior', 'expired', 'member', 'coupon'.
Raises InputError for missing, undeclared, or non-bool inputs, and OutOfScopeError
when check_scope is True and the inputs violate an assumption.
"""
values = _checked_inputs(inputs, ("student", "senior", "expired", "member", "coupon"), check_scope)
if check_scope:
_require_in_scope(values)
output_discount_value = _compute_output_discount(values["student"], values["senior"], values["expired"], values["member"], values["coupon"])
return output_discount_value
def evaluate(inputs: Mapping[str, bool], *, check_scope: bool = True) -> Dict[str, bool]:
"""Evaluate every output (declared order); each output is computed once.
Required inputs: 'student', 'senior', 'expired', 'member', 'coupon'.
Raises InputError for missing, undeclared, or non-bool inputs, and OutOfScopeError
when check_scope is True and the inputs violate an assumption.
"""
values = _checked_inputs(inputs, ("student", "senior", "expired", "member", "coupon"), check_scope)
if check_scope:
_require_in_scope(values)
output_discount_value = _compute_output_discount(values["student"], values["senior"], values["expired"], values["member"], values["coupon"])
return {
"discount": output_discount_value,
}
PostgreSQL
-- Tangibool PostgreSQL export (tangibool.postgresql/1)
-- Target: PostgreSQL 16 or later with typed boolean inputs; tested with PostgreSQL 18.3 (PGlite 0.5.8).
-- Not a claim of compatibility with other SQL dialects.
-- Model: not stated
-- Source revision: reference
-- Interpretation status: not stated
-- Exporter: 1.0.0 (engine 1.0.0; semantics tangibool-semantics/1)
-- Logic digest: a7ccaac3652524d0b2342e0bc0961ef98c69958628e3ef40fb5cadf1fd7ebdd8
-- Assumptions digest: d58ee1ad38e23e5093e4baa1047b5ae70d6972e08f555e34ac3fa16df63c4a78
-- Mode: decision
--
-- Read-only: this file contains only WITH / VALUES / SELECT statements. No DDL, DML,
-- procedures, credentials, network access, or database changes. The expressions are pure
-- Boolean expressions, so their result does not depend on SQL evaluation order.
--
-- NON-NULL INPUT PRECONDITION: NULL is not a truth value of this rule. Every fragment below
-- is defined only when every input column it reads is a non-NULL boolean. The guard template
-- (section 2) marks any NULL input as 'invalid_input' and any row that violates the
-- assumptions as 'out_of_scope', and fills output columns only for 'ok' rows; a NULL in an
-- output column of another row is an envelope marker, not a third truth value. Never wrap
-- the fragments in COALESCE(..., FALSE) or otherwise choose a meaning for unknown inputs.
-- This evaluates the supplied model; it does not show that the model is a complete, legal,
-- or safe statement of a real-world rule.
--
-- Input columns (stable ID: name -> column):
-- v_97a451a60f14: student -> "in_student"
-- v_9373a966ab63: senior -> "in_senior"
-- v_7a1672e8b8cb: expired -> "in_expired"
-- v_dbfd54032935: member -> "in_member"
-- v_67d46adf341f: coupon -> "in_coupon"
-- Output columns:
-- f_8a13877dfb35: discount -> "out_discount"
-- Assumptions (scope K; exported separately and never folded into an output):
-- none; every complete input row is in scope.
-- ----------------------------------------------------------------------------------------------
-- 1. Expression fragments (parenthesised; non-NULL boolean inputs required)
-- ----------------------------------------------------------------------------------------------
--
-- [out_discount] output discount (stable ID f_8a13877dfb35)
-- discount := (student OR senior) AND NOT expired AND (member OR coupon)
-- PRECONDITION: "in_student", "in_senior", "in_expired", "in_member", "in_coupon" are non-NULL booleans.
-- (("in_student" OR "in_senior") AND (NOT "in_expired") AND ("in_member" OR "in_coupon"))
--
-- ----------------------------------------------------------------------------------------------
-- 2. Guard template (read-only SELECT over an inputs list)
-- ----------------------------------------------------------------------------------------------
-- Replace the example rows between the markers with your own rows, or replace the inputs
-- CTE with a SELECT that provides the boolean columns listed in the header. status is
-- 'invalid_input' when any input is NULL, 'out_of_scope' when the assumptions are false, and
-- 'ok' otherwise; output columns are filled only for 'ok' rows (NULL elsewhere is an
-- envelope marker). Assumption columns are shown for rows with complete inputs.
WITH inputs ("row_id", "in_student", "in_senior", "in_expired", "in_member", "in_coupon") AS (
-- tangibool:example-rows:begin
VALUES
(1, FALSE, FALSE, FALSE, FALSE, FALSE),
(2, TRUE, TRUE, TRUE, TRUE, TRUE),
(3, NULL::boolean, FALSE, FALSE, FALSE, FALSE)
-- tangibool:example-rows:end
),
checked AS (
SELECT
inputs.*,
CASE
WHEN "in_student" IS NULL OR "in_senior" IS NULL OR "in_expired" IS NULL OR "in_member" IS NULL OR "in_coupon" IS NULL THEN 'invalid_input'
ELSE 'ok'
END AS "status"
FROM inputs
)
SELECT
"row_id",
"in_student",
"in_senior",
"in_expired",
"in_member",
"in_coupon",
"status",
CASE WHEN "status" = 'ok' THEN (("in_student" OR "in_senior") AND (NOT "in_expired") AND ("in_member" OR "in_coupon")) END AS "out_discount"
FROM checked
ORDER BY "row_id";
SMT-LIB
; Tangibool SMT-LIB export (tangibool.smtlib/1) ; Profile: SMT-LIB 2.6 Boolean subset (QF_UF): Bool constants, define-fun, let, push/pop, assert, check-sat, echo. ; Tested with Z3 5.1.0 (z3-solver 5.2.0, WebAssembly build). ; Model: not stated ; Source revision: reference ; Interpretation status: not stated ; Exporter: 1.0.0 (engine 1.0.0; semantics tangibool-semantics/1) ; Logic digest: a7ccaac3652524d0b2342e0bc0961ef98c69958628e3ef40fb5cadf1fd7ebdd8 ; Assumptions digest: d58ee1ad38e23e5093e4baa1047b5ae70d6972e08f555e34ac3fa16df63c4a78 ; Mode: decision ; ; Reading results: each query block states what sat and unsat mean for its question. A sat ; answer comes with a witness or counterexample (ask for it with (get-model) after sat only); ; unsat settles that scoped query and is solver-checked, not an independently checked proof ; certificate; unknown settles nothing. Blocks are scoped with push/pop, so assertions never ; accumulate across questions. This checks the supplied model, not whether it is a complete, ; legal, or safe statement of a real-world rule. ; ; Symbols (stable ID: name -> symbol): ; v_97a451a60f14: student -> in_student ; v_9373a966ab63: senior -> in_senior ; v_7a1672e8b8cb: expired -> in_expired ; v_dbfd54032935: member -> in_member ; v_67d46adf341f: coupon -> in_coupon ; f_8a13877dfb35: discount -> out_discount (set-option :produce-models true) (set-info :smt-lib-version 2.6) (set-logic QF_UF) ; ---- Inputs (declared order) (declare-const in_student Bool) ; student (declare-const in_senior Bool) ; senior (declare-const in_expired Bool) ; expired (declare-const in_member Bool) ; member (declare-const in_coupon Bool) ; coupon ; ---- Outputs (dependencies first) ; output discount (stable ID f_8a13877dfb35): (student OR senior) AND NOT expired AND (member OR coupon) (define-fun out_discount () Bool (and (or in_student in_senior) (not in_expired) (or in_member in_coupon))) ; ---- Assumptions (the scope K; never folded into an output) ; K: conjunction of the enabled, confirmed assumptions (true when there are none) (define-fun K () Bool true) ; ---- Definitions only: nothing is asserted and no check is run. ; Add (assert ...) and (check-sat) inside (push 1) ... (pop 1) to ask a question.
LaTeX
discount = \left(\mathit{student} + \mathit{senior}\right) \cdot \overline{\mathit{expired}} \cdot \left(\mathit{member} + \mathit{coupon}\right)The common slip
Expecting a Karnaugh map for a five-variable rule. The engine's map covers up to four variables and reports that the map is not available here rather than drawing something incomplete. The 32-row table, the four-term DNF and the exact checks carry the full analysis; nothing about the rule is left unchecked.
Questions
Why are the minterm numbers so spread out?
With student as the most significant bit and coupon as the least, each qualifying row needs expired FALSE, which fixes the middle bit, and at least one bit in each of the two pairs. The nine rows come in three groups of three, 9 to 11, 17 to 19 and 25 to 27, one group per status combination.
Related
Operators and gates
- NOT gate (inverter): truth table, symbol and the NOT operator
- AND gate: truth table for 2, 3 and 4 inputs, symbol and expression
- OR gate: truth table for 2, 3 and 4 inputs, inclusive or explained
Tools
- Truth table generator: any Boolean expression, up to 12 variables, with intermediate columns
- Boolean algebra calculator and simplifier with steps (every law named and verified)
- Karnaugh map solver: 2 to 4 variables, groups, SOP and POS, don’t-cares from assumptions
See also
- Eligibility rules: the pattern, the usual exceptions and the tests
- Truth table generator: any Boolean expression, up to 12 variables, with intermediate columns
- Loan eligibility: income_ok AND (credit_ok OR guarantor) AND NOT bankrupt
- Free shipping rule: (over_50 OR prime) AND NOT oversized AND domestic
- Decision table: meaning and examples
- Karnaugh map solver: 2 to 4 variables, groups, SOP and POS, don’t-cares from assumptions
Worked examples
Generated from the Tangibool engine, semantics tangibool-semantics/1, engine 1.0.0, build . Every table, map, simplification and verdict on these pages was computed by the Tangibool engine when the site was built, and every claim was re-checked by the same exact checker the app uses. Limits are stated where they apply. © 2026 Foreranger LTD.