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# Natural Language Toolkit: Semantic Interpretation
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#
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# Copyright (C) 2001-2020 NLTK Project
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# Author: Ewan Klein <ewan@inf.ed.ac.uk>
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# URL: <http://nltk.org/>
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# For license information, see LICENSE.TXT
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"""
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NLTK Semantic Interpretation Package
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This package contains classes for representing semantic structure in
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formulas of first-order logic and for evaluating such formulas in
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set-theoretic models.
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>>> from nltk.sem import logic
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>>> logic._counter._value = 0
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The package has two main components:
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- ``logic`` provides support for analyzing expressions of First
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Order Logic (FOL).
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- ``evaluate`` allows users to recursively determine truth in a
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model for formulas of FOL.
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A model consists of a domain of discourse and a valuation function,
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which assigns values to non-logical constants. We assume that entities
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in the domain are represented as strings such as ``'b1'``, ``'g1'``,
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etc. A ``Valuation`` is initialized with a list of (symbol, value)
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pairs, where values are entities, sets of entities or sets of tuples
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of entities.
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The domain of discourse can be inferred from the valuation, and model
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is then created with domain and valuation as parameters.
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>>> from nltk.sem import Valuation, Model
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>>> v = [('adam', 'b1'), ('betty', 'g1'), ('fido', 'd1'),
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... ('girl', set(['g1', 'g2'])), ('boy', set(['b1', 'b2'])),
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... ('dog', set(['d1'])),
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... ('love', set([('b1', 'g1'), ('b2', 'g2'), ('g1', 'b1'), ('g2', 'b1')]))]
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>>> val = Valuation(v)
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>>> dom = val.domain
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>>> m = Model(dom, val)
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"""
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from nltk.sem.util import parse_sents, interpret_sents, evaluate_sents, root_semrep
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from nltk.sem.evaluate import (
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Valuation,
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Assignment,
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Model,
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Undefined,
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is_rel,
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set2rel,
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arity,
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read_valuation,
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)
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from nltk.sem.logic import (
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boolean_ops,
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binding_ops,
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equality_preds,
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read_logic,
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Variable,
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Expression,
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ApplicationExpression,
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LogicalExpressionException,
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)
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from nltk.sem.skolemize import skolemize
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from nltk.sem.lfg import FStructure
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from nltk.sem.relextract import extract_rels, rtuple, clause
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from nltk.sem.boxer import Boxer
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from nltk.sem.drt import DrtExpression, DRS
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# from nltk.sem.glue import Glue
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# from nltk.sem.hole import HoleSemantics
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# from nltk.sem.cooper_storage import CooperStore
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# don't import chat80 as its names are too generic
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