test(layout): differential coverage for the band-merge anchor rule

- banded_layout_rejects_creeping_drift: a band within tolerance of the moving union but 36pt from the founder must not join the run — the case the anchor rule exists for; the pre-anchor union admitted it. - Reword the founder-anchor chain test as the invariant lock it is. - Note at the merge site why a reject-overlapping-unions guard is unimplementable: detect_columns returns contiguous partitions whose adjacent regions share boundary coordinates, so the check degenerates to exact-equality matching and rejects every legitimate merge; the boundary-disagreement zone is bounded by GUTTER_TOLERANCE and split proportionally by greatest-overlap bucketing.
fix(layout): anchor band-merge matching on the founding band's columns
2026-08-18 10:55:35 -07:00 · 2026-08-18 10:40:01 -07:00 · 2026-08-18 10:10:16 -07:00 · 2026-08-18 09:44:17 -07:00 · 2026-08-18 07:38:09 -07:00 · 2026-08-17 21:38:52 -07:00
2 changed files with 949 additions and 58 deletions
@@ -2,9 +2,19 @@

 # BePriced?

-*Commercial real estate pricing* **C O M M E R C I A L R E A L E S T A T E** pricingisliketheweather:everyonetalks *needs disciplined and systematic*about it, but few understand it. Most observers base “appropriate” real estate *analysis of the data.* pricing on historical norms. The cap rate—anindicatorofvaluerelativetosta- bilized net operating income (NOI) before capital expenditures, tenant improvement,andleasingcommissions— isthemostcommonlyusedmetricofreal estate pricing. But cap rates have been largelyunresponsivetoalternativeratesof return available to investors, with the **P E T E R L I N N E M A N** exception of BBB bonds, throughout
+*Commercial real estate pricing*

-8 4 Z E L L / L U R I E R E A L E S T A T E C E N T E R
+*needs disciplined and systematic*
+
+*analysis of the data.*
+
+**C O M M E R C I A L R E A L E S T A T E** pricingisliketheweather:everyonetalks about it, but few understand it. Most observers base “appropriate” real estate pricing on historical norms. The cap rate—anindicatorofvaluerelativetosta- bilized net operating income (NOI) before capital expenditures, tenant improvement,andleasingcommissions— isthemostcommonlyusedmetricofreal estate pricing. But cap rates have been largelyunresponsivetoalternativeratesof return available to investors, with the exception of BBB bonds, throughout
+
+C E N T E R
+
+**P E T E R L I N N E M A N**
+
+8 4 Z E L L / L U R I E R E A L E S T A T E

 **Table I:** Cap rate correlations **Cap Rate Correlation With:*** **BBB Corp** **10-Year Bond Yield S&P Dividend** **Treasury (10-15 yr) Yield** Multifamily 0.187 0.771 0.068 Industrial-0.221 0.748-0.307 CBD Office-0.449 0.694-0.458 Retail-0.181 0.649-02.58

@@ -13,9 +23,11 @@
 12 10 8 Percent 6 4 2 1982 1986 1990 1994 1998 2002 2006
 Apartment Retail ndustrial 10-yr reasury CBD Office

-most of the past twenty-five years (Table presented in Figure 2 with an eighteen-
+most of the past twenty-five years (Table
+
+I). Such a relationship defies investment theory,asrealestatepricingshouldchange as property risks and the returns of alter- nativeinvestmentschange. Figure1displaysNCREIFcapratesby property type compared to the ten-year Treasury yield. Because the National Council of Real Estate Investment Fiduciaries (NCREIF) cap rate data is seriouslyflawedduetoappraisallags,itis
+presented in Figure 2 with an eighteen- monthlag.Thisdataprovidesanoverview ofthepricingofinstitutionalqualityreal estate.Figure2reflectsthesecapratesnet of the ten-year Treasury yield. Since cap rate spreads are highly correlated across propertytypes(TableII),wecanspeakof “cap rates” without reference to property type with little loss of insight. Cap rate spreadswerenegativeintheearlytomid- 1980s, when purchasing real estate was

-I). Such a relationship defies investment monthlag.Thisdataprovidesanoverview theory,asrealestatepricingshouldchange ofthepricingofinstitutionalqualityreal as property risks and the returns of alter-estate.Figure2reflectsthesecapratesnet nativeinvestmentschange. of the ten-year Treasury yield. Since cap Figure1displaysNCREIFcapratesby rate spreads are highly correlated across property type compared to the ten-year propertytypes(TableII),wecanspeakof Treasury yield. Because the National “cap rates” without reference to property Council of Real Estate Investment type with little loss of insight. Cap rate Fiduciaries (NCREIF) cap rate data is spreadswerenegativeintheearlytomid- seriouslyflawedduetoappraisallags,itis 1980s, when purchasing real estate was
 R E V I E W 8 5

 **Figure 2:** Capratespreadsover10-yearTreasury
Author	SHA1	Message	Date
Abimael Martell	943fcd8722	test(layout): differential coverage for the band-merge anchor rule - banded_layout_rejects_creeping_drift: a band within tolerance of the moving union but 36pt from the founder must not join the run — the case the anchor rule exists for; the pre-anchor union admitted it. - Reword the founder-anchor chain test as the invariant lock it is. - Note at the merge site why a reject-overlapping-unions guard is unimplementable: detect_columns returns contiguous partitions whose adjacent regions share boundary coordinates, so the check degenerates to exact-equality matching and rejects every legitimate merge; the boundary-disagreement zone is bounded by GUTTER_TOLERANCE and split proportionally by greatest-overlap bucketing.	2026-08-18 10:55:35 -07:00
Abimael Martell	273c27b995	fix(layout): anchor band-merge matching on the founding band's columns The merge comparison ran against the widened union, whose gutter is the intersection of its constituents' gutters. Across a chain of one-directionally drifting bands that intersection can walk past GUTTER_TOLERANCE and reject a band identical to the run's own first member. Compare candidates against the founding band's raw columns instead: the run's column system is defined by its founder, so drift can no longer accumulate in either direction. Union widening is kept for item bucketing only.	2026-08-18 10:40:01 -07:00
Abimael Martell	02cf9affa7	fix(layout): keep figure placeholders out of band whitespace probes An image placeholder sitting between two matching column bands is the very figure float whose flow-through the band merge exists for, yet it read as content twice: its glyph box filled the occupancy gap (blocking the cut) and the merge probe counted it as separator content (blocking the merge). Both probes now see text layout items only.	2026-08-18 10:10:16 -07:00
Abimael Martell	27c43759ae	docs(layout): record why the band wide-item test is per-item Assembling same-baseline fragments into runs before the wide test was implemented and measured against the reading-order benchmark: word-gap and gutter-gap distributions overlap in real documents, so assembled runs fused narrow-guttered column pairs into page-wide lines, emptied the occupancy, and disengaged banding on pages it rescues — a measured regression with no measured win. Keep the per-item test (a fragmented separator can suppress a cut, which only misses an engagement) and document the boundary for future attempts.	2026-08-18 09:44:17 -07:00
Abimael Martell	c7b4f8c68e	feat(layout): banded region segmentation for vertically-changing column layouts Pages whose column structure changes down the page (newsletter bands, figure-split flows, a three-column strip inside a two-column page) cannot be represented by one full-height column set: the projection profile either finds nothing and Y-interleaves the columns, or weaves the odd band's text into the wrong buckets. - Split pages into horizontal bands at full-width whitespace gaps (wide spanning items are excluded from occupancy — separators sit inside the very gaps being sought), detect columns independently per band, and re-merge consecutive bands with matching gutters across empty gaps so figure floats keep flowing down their columns while headline-separated bands stay independent. - Engage only on contradicting evidence: a prose-validated band whose column count differs from the page-level structure. Pages the flat column model already explains keep their current ordering. - Read short prose columns (5-14 lines, >=60% width fill on >=60% of lines in every column) as newspaper instead of Y-interleaving them as tabular. Kept as a standalone reading-order refinement so the table pipeline's is_newspaper_layout veto is unaffected. - Split ordering entry points: order_multi_column_region keeps every page-level defense; order_validated_band (banded planner only) trusts validated bands, skipping line-count minimums and straggler splitting that would misfire on Y-cohesive bands.	2026-08-18 07:38:09 -07:00
Abimael Martell	74ebce430c	fix(layout): accept figure-diluted prose columns via a sustained full-line run (#417 ) * fix(layout): accept figure-diluted prose columns via a sustained full-line run The columns_have_prose gate (added against table/TOC/checklist false-splits in relative-valley detection) requires >=40% of a column's lines to span >=45% of its width. A genuine prose column hosting a figure and caption dilutes that global ratio below the bar — measured 0.38 on a two-column research page — so the valley is rejected, the page falls back to single-column, and same-baseline items from both columns merge across the gutter into woven sentences. Accept a column that contains a sustained paragraph block instead: at least 6 consecutive full-width lines. The scattered layouts the gate exists to reject cannot produce an unbroken run of full lines, and the other guards (column width, minimum lines, items-per-line) still apply. Tests pin both directions; regression corpus is unchanged. * docs(layout): restore columns_have_prose rustdoc displaced by hoisted const The hoisted LINE_FILL_THRESHOLD landed between the gate's rustdoc block and the items that followed, absorbing the function's documentation onto the constant. The docs return to the function, extended to cover the sustained-run acceptance path.	2026-08-17 21:38:52 -07:00