Original question and givens
Use deterministic single-tape states=[scan, accept, reject], input_alphabet=[a20, b20], tape_alphabet=[a20, b20, _], blank=_, start=scan, accept=accept, reject=reject, transitions=[[scan, a20, scan, a20, R], [scan, b20, accept, b20, S], [scan, _, scan, _, S]]. Each transition is [state,read,next,write,L/R/S]; keys [state,read] are unique and halting states have no outgoing transitions. Input symbols form a blank-free tape subset. The integer-indexed tape is blank at every unlisted cell, with configuration [state,head,sparse nonblank tape]; L may move left of0. Canonical answer transitions/tape cells retain the source sort convention. Target=b20, legal target-free input=[a20, a20]. Give (states, input_alphabet, tape_alphabet, transitions, target_symbol, input, loop_configuration, next_configuration, exact_self_loop, decider, boundary).
G001 — Use deterministic single-tape states=[scan, accept, reject], input_alphabet=[a20, b20], tape_alphabet=[a20, b20, _], blank=_, start=scan, accept=accept, reject=reject, transitions=[[scan, a20, scan, a20, R], [scan, b20, accept, b20, S], [scan, _, scan, _, S]]. Each transition is [state,read,next,write,L/R/S]; keys [state,read] are unique and halting states have no outgoing transitions. Input symbols form a blank-free tape subset. The integer-indexed tape is blank at every unlisted cell, with configuration [state,head,sparse nonblank tape]; L may move left of0. Canonical answer transitions/tape cells retain the source sort convention. Target=b20, legal target-free input=[a20, a20]. Give (states, input_alphabet, tape_alphabet, transitions, target_symbol, input, loop_configuration, next_configuration, exact_self_loop, decider, boundary).
Step-by-step derivation
S001 · implies
Before
source roles = [tm-recognizer-loop-boundary]
After
derived = [[states, input_alphabet, tape_alphabet, transitions, target_symbol, input, loop_configuration, next_configuration, exact_self_loop, decider, boundary]]
Conditions: none
List the full source field order without JavaScript,keeping original data,Boolean flags,mathematical objects and nonclaims distinct.
Step identifiers and dependencies
Rule: source_ordered_fields_without_JS · Uses: G001
S002 · implies
Before
source roles = [[scan, accept, reject], [a20, b20], [a20, b20, _], _, scan, accept, reject, [[scan, a20, scan, a20, R], [scan, b20, accept, b20, S], [scan, _, scan, _, S]]]
After
derived = [[accept, reject, scan], [a20, b20], [_, a20, b20], [[scan, _, scan, _, S], [scan, a20, scan, a20, R], [scan, b20, accept, b20, S]], Yes]
Conditions: none
All three lists are nonempty and unique;input is a blank-free tape subset,but state and alphabet labels may overlap.Source NUL-joined(from,read) keys are unique,and halting states have no outgoing rules.A partial table is legal,not filled with rejection;transition collation and UTF16 set order differ.
Step identifiers and dependencies
Rule: TM_complete_signature_partial_transition_table_allowed · Uses: G001, S001
S003 · implies
Before
source roles = [b20, Yes, [[accept, reject, scan], [a20, b20], [_, a20, b20], _, scan, accept, reject, [[scan, _, scan, _, S], [scan, a20, scan, a20, R], [scan, b20, accept, b20, S]]]]
After
derived = [[[accept, reject, scan], [a20, b20], [_, a20, b20], _, scan, accept, reject, [[scan, _, scan, _, S], [scan, a20, scan, a20, R], [scan, b20, accept, b20, S]]], Yes]
Conditions: none
Require the exact full signature and all schema transitions;sample successful traces do not certify an arbitrary TM.
Step identifiers and dependencies
Rule: TM_EXACT_canonical_scan_schema_not_sampled_machine · Uses: G001, S002
S004 · implies
Before
source roles = [[a20, a20], b20, [[scan, _, scan, _, S], [scan, a20, scan, a20, R], [scan, b20, accept, b20, S]]]
After
derived = [[scan, 2, [[0, a20], [1, a20]]], [scan, 2, [[0, a20], [1, a20]]], Yes, No]
Conditions: none
Copy/R across every target-free input symbol reaches blank at head|w|.The blank rule writes blank,stays S and remains scan,so the entire configuration repeats.Determinism proves this input loops forever,refuting this recognizer as a decider,not by budget exhaustion.
Step identifiers and dependencies
Rule: TM_actual_target_free_input_reaches_EXACT_blank_SELFLOOP · Uses: G001, S003
Result
([accept, reject, scan], [a20, b20], [_, a20, b20], [[scan, _, scan, _, S], [scan, a20, scan, a20, R], [scan, b20, accept, b20, S]], b20, [a20, a20], [scan, 2, [[0, a20], [1, a20]]], [scan, 2, [[0, a20], [1, a20]]], Yes, No, explicit_blank_self_loop_proves_this_recognizer_is_not_a_decider_on_the_target_free_input)
The full substitutions and premise checks give the original answer; source identity,format and status are unchanged.