Alphabeta Math
Pipeline-generated
How statement and proof provenance work

The first chip identifies the source of the statement or construction; the second identifies the source of its local proof or verification.

  • Literature-sourced: the exact statement appears in a cited source; only wording and notation differ.
  • AI-adapted: a semantically identical restatement of literature-sourced material, modulo indexing, notation, and boundary cases adopted by the library.
  • AI-generated: a genuinely novel statement formulated by AI, with no source for the claim itself.

These labels describe origin, not correctness: citations and verification chips remain separate evidence.

Generalized Bayes loss updates and temperature calibration — Examples

1 · Prerequisites

2 · Summary

Finite and countable constructions make the normalizer and temperature conditions explicit. The unit-temperature likelihood example is a finite Bayesian model calculation; rescaling the loss shows the equivalent change in effective temperature. A separate dyadic prior has an infinite normalizer, and a two-state experiment produces a posterior credible set with zero frequentist coverage. Each calculation states its prior, loss and temperature locally; the coverage and likelihood examples also specify their finite sampling experiments. None asserts a general coverage theorem.

3 · Logical flowchart

4 · Definitions, theorems and proofs

None yet.

5 · Examples, counterexamples and false statements

ExampleConstruction: AI-generatedVerification: AI-generatedjudge pass (gpt-6-luna)Open item page →

A measurable loss can have an infinite normalizer

Example

Let Θ=N with its power-set sigma-algebra, and put ak=(1/2)k+1 for k∈N. Define the prior π:=∑k=0∞akδk, where δk is the Dirac measure at k. The geometric-series formula gives ∑k≥0ak=1, so π is a probability measure. Define the real-valued loss ℓ(k):=log⁡ak. At temperature w=1, every unnormalized atom has mass ake−ℓ(k)=1, and the normalizer is infinite; therefore the loss update is not defined.

Facts & Assumptions

Given: The von Neumann natural numbers N, their power-set sigma-algebra, weights ak=(1/2)k+1, and Dirac measures δk.

[F1]

Generalized Bayes loss update and temperature: at fixed w>0, Z=∫e−wℓ dπ must be finite and positive for the update to be defined.

[F2]

A countable discrete measurable space is standard Borel: every nonempty at-most-countable set with its power-set sigma-algebra is standard Borel.

[F3]

Finite, countably infinite, countable, uncountable: a set equinumerous with N is at-most-countable.

[F4]

The natural numbers N (von Neumann): 0∈N and N is closed under successor.

[F5]

Nonnegative scalar multiples and countable weighted sums of measures are measures: a countable nonnegative weighted sum of measures on one measurable space is a measure.

[F6]

The Dirac set function at a point: δk(A)=1 when k∈A and is zero otherwise.

[F7]

A Dirac set function is a probability measure: each δk is a probability measure.

[F8]

Probability measures and probability spaces: a probability measure has total mass one.

[F9]

The principle of mathematical induction: a property holding at zero and preserved by successor holds for all natural numbers.

[F10]

Integer powers am: b0=1 and bk+1=bkb for natural k.

[F12]

The natural logarithm as the inverse of the exponential function: log⁡ is inverse to exp⁡ on (0,∞).

[F13]

The exponential is positive and satisfies exp⁡(−x)=1/exp⁡(x): exp⁡(t)>0 and exp⁡(−t)=1/exp⁡(t).

[F14]

Nonnegative simple measurable functions: a finite nonnegative linear combination of indicators of measurable sets is a nonnegative simple measurable function.

[F15]

The nonnegative Lebesgue integral: the nonnegative integral is the supremum of the integrals of nonnegative simple minorants, with values in [0,+∞].

[F16]

The integral of a nonnegative simple function: the integral of a simple function represented on disjoint measurable sets is the sum of its coefficient times the measure of each set.

[F17]

The nonnegative integral agrees with the simple integral on simple functions: the nonnegative integral of a simple function equals its simple integral.

[F18]

Monotonicity and nonnegative homogeneity of the nonnegative integral: if 0≤f≤g, then ∫f dπ≤∫g dπ.

[F20]

Every complete ordered field is Archimedean: in a complete ordered field, for every x there is a natural n≥1 with x<n.

[F21]

Absolute value in an ordered field: if b≥0, then ∣b∣=b.

[F22]

Ordered field: products of positive reals are positive.

[F24]

Laws of finite sums and finite products: finite sums scale by a real constant, ∑k<ncuk=c∑k<nuk.

[F25]

Series, partial sums, convergence and the sum, divergence, and the tail series: a convergent series sums to the limit of its finite partial sums.

[F26]

Algebra of limits: sums, scalar multiples, products and quotients: scaling a convergent sequence by a fixed real constant scales its limit by that constant.

[F27]

A series of nonnegative terms converges iff its partial sums are bounded, and then the sum is their supremum: for nonnegative terms, the usual convergent series sum is the supremum of its finite partial sums.

[F28]

Series in the nonnegative extended real line: the nonnegative extended sum is the supremum of its finite partial sums.

[F29]

Nonnegative scalar multiples and countable weighted sums of measures: the countable weighted sum is evaluated pointwise by the nonnegative extended sum of its weighted measures.

Verification

1.1F3F4F2given

The identity map shows N is equinumerous with itself, hence at-most-countable by [F3]; [F4] makes it nonempty. Therefore [F2] shows (Θ,P(Θ)) is standard Borel.

1.2F21F10F23F22F9F19givenalgebra

Put b=1/2. Ordered-field arithmetic gives 0<b<1, so [F21] gives ∣b∣=b<1. The powers are positive: b0=1>0 by [F10] and [F23], and if bk>0, then bk+1=bkb>0 by [F10] and [F22]. Induction [F9] gives ak=bk+1>0 for every k.

2.1F11F10F24F25F26F27F28step 1.2algebra

By [F11], ∑k=0∞bk=1/(1−b). For every N, recursion [F10] and finite-sum scaling [F24] give ∑k<N+1ak=∑k<N+1bk+1=b∑k<N+1bk. The partial sums of ∑bk converge to 1/(1−b) by [F11] and [F25]; therefore [F26] gives ∑k=0∞ak=b/(1−b)=1. By [F27] and [F28], this usual series sum is also the nonnegative extended sum of the coefficients used in the weighted measure.

2.2F12F13step 1.2given

Since ak>0, ℓ(k)=log⁡ak is finite. Every inverse image of a Borel subset of R is a subset of N, hence is in P(N); therefore ℓ is measurable. By [F12]–[F13], e−ℓ(k)=1/ak, so the normalizer is Z=∫e−ℓ dπ.

3.1F5F7F6F28F29step 2.1F8algebra

By [F5] and [F7], π=∑k≥0akδk is a measure. Its total mass is π(Θ)=∑k≥0akδk(Θ)=∑k≥0ak=1 by [F6], [F28], [F29], and step 2.1, so [F8] makes π a probability. For each k, [F6] gives π({k})=ak.

4.1F14F13F16F17step 3.1F18F15step 2.2algebra

For each N∈N, set sN:=∑k=0Nak−11{k}. It is a nonnegative simple function by [F14], and 0≤sN≤e−ℓ: there is equality at k≤N, and for k>N the left side is zero while e−ℓ(k)>0 by [F13]. By [F16]–[F17] and step 3.1, ∫sN dπ=∑k=0Nak−1π({k})=N+1. Thus [F18] yields Z≥N+1 for every N.

5.1F19F20step 4.1F15F1contradiction∎

If Z were finite, [F19]–[F20] would give N∈N, N≥1, with Z<N. Step 4.1 gives Z≥N+1, a contradiction. Since [F15] places Z in [0,+∞], it follows that Z=+∞. The finite-positive condition in [F1] therefore fails, so no generalized Bayes update is defined.

CounterexampleConstruction: AI-generatedVerification: AI-generatedjudge pass (gpt-6-luna)Open item page →

A generalized Bayes credible set can have zero coverage

Statement refuted

A positive temperature and a proper generalized Bayes loss update alone guarantee that every posterior 0.95-credible set has frequentist coverage at least 0.95 under the sampling experiment.

Facts & Assumptions

Given: The finite parameter space Θ={0,1}, singleton observation space X={x0}, prior (1/100,99/100), sampling laws P0=P1=δx0, and the displayed loss at w=1.

[F1]

A countable discrete measurable space is standard Borel: a nonempty at-most-countable set with its power-set sigma-algebra is standard Borel.

[F2]

Probability measures and probability spaces: a probability measure has total mass one.

[F3]

The Dirac set function at a point: δx0(A)=1 if x0∈A and is zero otherwise.

[F4]

A Dirac set function is a probability measure: each Dirac set function is a probability measure.

[F5]

Statistical experiments: an experiment consists of a sample measurable space, parameter set and a probability law on the sample space for each parameter.

[F6]

Generalized Bayes loss update and temperature: if 0<Z=∫e−wℓx dπ<∞, the update is the normalized measure with that density.

[F7]

A finite-normalizer loss update is a probability measure: each update with a finite positive normalizer is a probability measure.

[F9]

The exponential function is strictly increasing: the exponential is strictly increasing on R.

[F10]

Confidence sets and coverage: a confidence-set procedure maps data to parameter subsets with measurable membership sections; coverage at θ is the sampling probability that its set contains θ.

Counterexample

Let Θ={0,1} and X={x0}, each with its power-set sigma-algebra. Use prior π(0)=1/100, π(1)=99/100, and sampling laws P0=P1=δx0. At the sole observation x0, let ℓ(0,x0)=1 and ℓ(1,x0)=0, with temperature w=1. The singleton data-to-set rule C(x0)={1} is called 0.95-credible here when the update qx0 satisfies qx0(C(x0))≥0.95. It has posterior mass greater than 0.95, yet its coverage at true parameter 0 is zero.

1.1F1F2F3F5F6F8F7F4givenalgebra

The parameter and data spaces are nonempty finite sets, so [F1] makes them standard Borel. The prior masses sum to one, hence [F2] makes π a probability. [F3]–[F5] show the sampling laws define a statistical experiment. [F6]–[F8] give the normalizer Z=1100e−1+99100e0, which is finite and positive. By [F7], the resulting update q is a probability measure.

2.1F9F8F6step 1.1algebra

Since −1<0, [F9] gives e−1<e0. Both are positive by [F8], and Z=1100e−1+99100e0<e0. Therefore q({1})=(99/100)e0Z>99100>0.95. Thus C(x0)={1} is a posterior credible set of mass greater than 0.95.

Verification

3.1F10step 1.1step 2.1algebra∎

Regard C as the data-to-set procedure with sole value C(x0)={1}. Its membership section for parameter 0 is empty, and for parameter 1 is {x0}; both are measurable. The coverage definition [F10] therefore applies, and at true parameter 0 it gives P0{x:C(x)∋0}=P0(∅)=0. This is below 0.95, refuting the proposed universal guarantee.

ExampleConstruction: AI-generatedVerification: AI-generatedjudge pass (gpt-6-luna)Open item page →

Rescaling loss changes the effective temperature

Example

Let Θ={0,1} with its power-set sigma-algebra and prior π(0)=p, π(1)=1−p for 0<p<1. At a fixed observation x0, let ℓx0(0)=a and ℓx0(1)=b with a≠b. For every w,c>0, replacing this loss section by cℓx0 at temperature w gives the same update as retaining ℓx0 at temperature cw. At any two distinct positive temperatures, the updates are different.

Facts & Assumptions

Given: The finite parameter space Θ={0,1} with its power-set sigma-algebra; an observation x0; 0<p<1; real loss-section values a≠b; and positive temperatures w,c,t1,t2 with t1≠t2.

[F1]

A countable discrete measurable space is standard Borel: every nonempty at-most-countable set with its power-set sigma-algebra is standard Borel.

[F2]

Probability measures and probability spaces: a probability measure is a measure of total mass one.

[F3]

Generalized Bayes loss update and temperature: when its normalizer is finite and positive, the update is the measure with density e−tℓ/Zt relative to the prior.

[F4]

A finite-normalizer loss update is a probability measure: each update with a finite positive normalizer is a probability measure.

[F5]

The exponential function is strictly increasing: the exponential is strictly increasing, hence injective, on R.

[F6]

Verification

1.1F1F2F6givenalgebra

The set Θ is nonempty and finite, so [F1] makes its power-set measurable space standard Borel. Since 0<p<1, the masses p and 1−p are positive and sum to one, so [F2] makes π a probability. For every t>0, the two real loss values give positive finite weights e−ta and e−tb by [F6]; their prior-weighted sum is therefore finite and positive.

2.1F3F4step 1.1algebra

By [F3]–[F4], the update qt=Gt,π,x0 has masses qt(0)=pe−tape−ta+(1−p)e−tb,qt(1)=(1−p)e−tbpe−ta+(1−p)e−tb. Consequently its odds satisfy qt(1)qt(0)=1−ppe−t(b−a)..

2.2step 1.1F3algebra

For θ∈Θ, the unnormalized weight after replacing ℓx0 by cℓx0 at temperature w is π(θ)e−wcℓx0(θ)=π(θ)e−(cw)ℓx0(θ). These are exactly the unnormalized masses for qcw. The two updates have the same finite positive normalizer by step 1.1, so their values on both singletons, and hence on every subset of Θ, agree.

3.1F5step 2.1algebra∎

Because b−a≠0 and t1≠t2, the real numbers −t1(b−a) and −t2(b−a) differ. Injectivity in [F5] makes their exponentials different. Multiplication by the fixed positive factor (1−p)/p preserves that difference, so step 2.1 gives distinct odds. On a two-point probability space the odds determine both singleton masses; therefore qt1≠qt2.

ExampleConstruction: AI-generatedVerification: AI-generatedOpen item page →

The unit-temperature likelihood update is ordinary Bayes in a finite model

Example

Let Θ={0,1} have prior masses π(0)=1/3 and π(1)=2/3. Let the observation space be X={0,1} and define sampling laws by P0(Y=1)=1/4, P0(Y=0)=3/4, P1(Y=1)=3/4, and P1(Y=0)=1/4. These finite spaces with power-set sigma-algebras are standard Borel, and the displayed laws define a statistical experiment. Take ℓ(θ,y)=−log⁡Pθ(Y=y) for every (θ,y)∈Θ×X. For observed y=1 at w=1, the unnormalized masses are 1/12 and 1/2, so the update is (1/7,6/7). The same values follow by conditioning the joint prior-sampling law on Y=1.

Facts & Assumptions

Given: The parameter and observation spaces {0,1} with power-set sigma-algebras, prior (1/3,2/3), and the four displayed sampling probabilities.

[F1]

A countable discrete measurable space is standard Borel: a nonempty at-most-countable set with its power-set sigma-algebra is standard Borel.

[F2]

Probability measures and probability spaces: a probability measure has total mass one.

[F3]

Statistical experiments: a statistical experiment consists of a sample measurable space, a parameter set, and a probability law on the sample space for each parameter.

[F4]

Generalized Bayes loss update and temperature: at w=1 the update weights are proportional to e−ℓ(θ,y) and are normalized by their integral against the prior.

[F5]

A finite-normalizer loss update is a probability measure: a finite-positive-normalizer update is a probability measure.

[F6]

The natural logarithm as the inverse of the exponential function: log⁡ is the inverse of exp⁡ on (0,∞).

[F7]

Conditional probability P(A∣B) for P(B)>0: in a finite probability space, Pr⁡(A∣B)=Pr⁡(A∩B)/Pr⁡(B) when Pr⁡(B)>0.

Verification

1.1F1F2F3givenalgebra

Both parameter and sample spaces are nonempty finite sets, so [F1] makes them standard Borel. The prior masses are nonnegative and sum to one; each pair of sampling probabilities is nonnegative and sums to one. By [F2] these are probability measures, and [F3] therefore gives the stated finite statistical experiment.

2.1F6F4step 1.1algebra

All four likelihoods are positive, so [F6] makes ℓ real-valued on Θ×X. Each parameter section is measurable because the parameter sigma-algebra is the power set, satisfying the loss hypotheses of [F4] for every y∈X. At y=1, the inverse relation in [F6] gives e−ℓ(θ,1)=elog⁡Pθ(Y=1)=Pθ(Y=1). Hence the unnormalized weights are π(0)P0(Y=1)=112,π(1)P1(Y=1)=12, and their normalizer is Z=1/12+1/2=7/12, finite and positive.

3.1F4F5step 2.1algebra

By [F4]–[F5], the update is a probability measure with q(0)=1/127/12=17,q(1)=1/27/12=67..

4.1F7step 1.1step 2.1step 3.1algebra∎

Define the joint masses by Pr⁡(θ,y)=π(θ)Pθ(Y=y). The four masses are 1/4,1/12,1/6,1/2 at (0,0),(0,1),(1,0),(1,1), respectively; they sum to one, and Pr⁡(Y=1)=7/12>0. Applying [F7] to each parameter singleton gives Pr⁡(θ=0∣Y=1)=1/127/12=17,Pr⁡(θ=1∣Y=1)=1/27/12=67. Thus the loss update equals the ordinary finite-model posterior at y=1.

Sources