Construct · 3 fields · 6 citations

Where does frontier collide?

One name. Different field. Different construct. One map.

● jingle · one word, three constructs Nearest construct by meaningportfolio selectioncompare the meanings
How to read this

Every construct on the map is compared with every other by the meaning of its definitions, and the closest one is surfaced here. The nearest construct to frontier is portfolio selection.

Hold this as a prompt, not a verdict. Two constructs sitting close in meaning is a reason to read them side by side and decide for yourself whether they are one idea under two names. It is not proof that they are. Compare the meanings in the Collider.

frontier3 CONSTRUCTSFrontier thesisTURNER · SETTLEMENT EDGEEfficient frontierMARKOWITZ · RISK-RETURNFrontier orbitalsFUKUI · MOLECULAR ORBITAL

Spokes are fields; dashed arcs are shared lineage. Tap a field for its definition, unit, and measures.

1894Frontier thesis1952Efficient frontier1952Frontier orbitals
2026

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History

The advancing edge of settlement

Frederick Jackson Turner's 1893 address The Significance of the Frontier in American History gave the word its meaning here: the frontier is the moving edge where settled society met land not yet settled by it, and Turner argued that the repeated experience of that edge shaped American democracy, individualism, and national character. His 1920 collection The Frontier in American History gathered and extended the argument. The referent is a zone and a process in human settlement and its social effects, not a curve of investment choices or a pair of electron orbitals.[1][2]

Unit
A settlement edge across historical time, described by its location and its social effects
Recovery means
Not applicable
Measured by
Traced through census settlement lines, land records, and historical narrative rather than a single scale

Finance

The boundary of optimal portfolios

Harry Markowitz's 1952 paper Portfolio Selection introduced the efficient frontier: the boundary of the set of investment portfolios that offer the highest expected return for each level of risk, where risk is measured by the variance of returns. His 1959 book Portfolio Selection: Efficient Diversification of Investments developed the full method for finding that boundary. The referent is a curve in risk-return space marking the best attainable trade-offs, not an edge of human settlement or a class of reactive orbitals.[3][4]

Unit
A curve in risk-return space, each point a portfolio's expected return and its variance
Recovery means
Not applicable
Measured by
Computed by mean-variance optimisation from the expected returns, variances, and covariances of the assets

Chemistry

the highest occupied and lowest unoccupied molecular orbitals, which largely govern how a molecule reacts.

Kenichi Fukui, Teijiro Yonezawa, and Haruo Shingu's 1952 paper A Molecular Orbital Theory of Reactivity in Aromatic Hydrocarbons introduced frontier orbitals: the highest occupied and the lowest unoccupied molecular orbitals, which sit at the outer boundary of a molecule's filled energy levels and largely govern how it reacts. Fukui's 1982 Role of Frontier Orbitals in Chemical Reactions laid out the mature theory that shared the 1981 Nobel Prize in Chemistry. The referent is a pair of electron orbitals that control chemical reactivity, not a boundary of portfolios or an edge of settlement.[5][6]

Unit
A molecule's highest occupied and lowest unoccupied orbitals, by energy and electron distribution
Recovery means
Not applicable
Measured by
Calculated by molecular orbital methods that give orbital energies and the electron coefficients at each atom

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Nearby collisions

portfolio3 fields · 3 citationsjingle · one word, three constructsdiversification4 fields · 4 citationsjingle · one word, four constructsrisk6 fields · 13 citationsjingle · one name, six constructs

References

  1. Turner, F. J. (1894). The significance of the frontier in American history. In Annual Report of the American Historical Association for the Year 1893 (pp. 197–227). Government Printing Office.
  2. Turner, F. J. (1920). The Frontier in American History. Henry Holt and Company.
  3. Markowitz, H. (1952). Portfolio selection. The Journal of Finance, 7(1), 77–91. https://doi.org/10.1111/j.1540-6261.1952.tb01525.x
  4. Markowitz, H. (1959). Portfolio Selection: Efficient Diversification of Investments. John Wiley & Sons.
  5. Fukui, K., Yonezawa, T., & Shingu, H. (1952). A molecular orbital theory of reactivity in aromatic hydrocarbons. The Journal of Chemical Physics, 20(4), 722–725. https://doi.org/10.1063/1.1700523
  6. Fukui, K. (1982). Role of frontier orbitals in chemical reactions. Science, 218(4574), 747–754. https://doi.org/10.1126/science.218.4574.747

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