Actual Euclidean histories · independent gcd witnesses · strict two-step halving

Constructive Euclidean execution and complexity

Fifteen independently checked constructive theorems produce complete beta-coded Euclidean histories, independent relational gcd witnesses, strict two-step halving and an actual linear step bound.

15 kernel- and Lean-verified Alpha-closed theorems · 9 conservative definitions · 8 notation dependencies

Alpha v34 checked-use · first admitted v21 · independently kernel and Lean verified; not Stable

Current library: Alpha v34, 4,223 checked-use theorems; Stable remains 432. Historical first admissions, original proof editions, and non-admitted aliases are preserved. Exact original first-admission records.

24 items
EC0001 euclidean_division_step_exists

A nonzero Euclidean divisor constructively yields an exact quotient and strictly smaller remainder.

Alpha v34 checked-use · first admitted v21 · independently kernel and Lean verified; not Stable
EC0002 euclidean_division_step_functional

Two exact bounded Euclidean divisions of the same inputs have identical quotients and remainders.

Alpha v34 checked-use · first admitted v21 · independently kernel and Lean verified; not Stable
EC0003 euclidean_next_division_step_exists

Every nonterminal Euclidean remainder constructively admits the next genuine bounded division.

Alpha v34 checked-use · first admitted v21 · independently kernel and Lean verified; not Stable
EC0004 euclidean_add_right_preserves_lt

Constructive strict natural order remains strict after adding the same right summand.

Alpha v34 checked-use · first admitted v21 · independently kernel and Lean verified; not Stable
EC0005 euclidean_two_step_quotient_nonzero

After one strict Euclidean decrease, the quotient of the next division cannot be zero.

Alpha v34 checked-use · first admitted v21 · independently kernel and Lean verified; not Stable
EC0006 euclidean_two_step_halving

Any two consecutive genuine bounded Euclidean divisions strictly halve the starting divisor: twice the second remainder is smaller.

Alpha v34 checked-use · first admitted v21 · independently kernel and Lean verified; not Stable
EC0007 euclidean_trace_bound_weaken

An already witnessed complete beta-coded history remains within the successor of its original linear step budget.

Alpha v34 checked-use · first admitted v21 · independently kernel and Lean verified; not Stable
EC0008 euclidean_trace_exists_up_to_linear

Bounded natural induction constructs an authentic complete Euclidean beta-history using at most B divisions whenever the divisor is at most B.

Alpha v34 checked-use · first admitted v21 · independently kernel and Lean verified; not Stable
EC0009 euclidean_trace_exists_linear

Every natural input pair admits an actual terminating Euclidean beta-trace whose exact division count is at most its initial divisor.

Alpha v34 checked-use · first admitted v21 · independently kernel and Lean verified; not Stable
EC000A euclidean_execution_zero_divisor

The zero-divisor boundary has an actual zero-step beta-history and returns the dividend as its checked relational gcd.

Alpha v34 checked-use · first admitted v21 · independently kernel and Lean verified; not Stable
EC000B euclidean_execution_gcd_correct

Every expanded Euclidean execution independently certifies its output against the original relational gcd specification.

Alpha v34 checked-use · first admitted v21 · independently kernel and Lean verified; not Stable
EC000C euclidean_execution_trace_correct

Every expanded Euclidean execution contains an actual complete beta-coded history, not an abstract oracle or opaque trace predicate.

Alpha v34 checked-use · first admitted v21 · independently kernel and Lean verified; not Stable
EC000D euclidean_execution_exists

All natural input pairs admit a fully expanded, beta-coded terminating Euclidean execution with a certified relational gcd output.

Alpha v34 checked-use · first admitted v21 · independently kernel and Lean verified; not Stable
EC000E euclidean_nonzero_execution_exists

For every nonzero initial divisor, an actual certified Euclidean execution exists and makes at least one division.

Alpha v34 checked-use · first admitted v21 · independently kernel and Lean verified; not Stable
EC000F euclidean_gcd_execution_linear_bound

Every pair has a complete actual beta-coded Euclidean execution, a genuinely certified gcd output, and the exact constructive linear bound steps <= initial divisor; the stronger BitLen bound remains open.

Alpha v34 checked-use · first admitted v21 · independently kernel and Lean verified; not Stable
PD0002 Lt(a,b)

Witness-defined strict order on natural numbers.

Conservative definition · notation layer 0
ND0001 Beta(b,c,i,x)

Exact hygienic Gödel-beta extraction; a signature-identical alias of checked BetaAt.

Conservative definition · notation layer 0
ND0009 ListCell(s,q,t)

The exact tagged natural-number list cell containing quotient q and tail t.

Conservative definition · notation layer 0
PD0003 Dvd(d,n)

The natural number d divides n.

Conservative definition · notation layer 0
PD0006 IsGCD(g,a,b)

g is a common divisor divisible by every common divisor.

Conservative definition · notation layer 1
ND0020 EuclideanExecution(a,b,g,k)

A complete beta-coded Euclidean quotient history together with an independently witnessed relational gcd; terminal-state identification is not asserted.

Conservative definition · notation layer 2

Only proof arrows are theorem dependencies. Definition arrows are hygienic abbreviations of exact first-order formulas and introduce no axiom or kernel symbol.