Question: Ernő Lendvai (February 6, 1925 – January 31, 1993) was one of the first music theorists to write on the appearance of the golden section and Fibonacci series and how these are implemented in Bartók's music, he also formulated the axis system, acoustic scale and alpha chord, an octatonic scale is any which number note musical scale?

Context articles: Hungarian minor scale
Psalms chord
Supertonic
Ernő Lendvai
Escala nordestina
Augmented major seventh chord
Scale of harmonics
Roman numeral analysis
Octatonic scale
Axis system

The Hungarian Minor scale, Double Harmonic minor scale, or Gypsy minor scale, is a type of combined musical scale.
 It is the fourth mode of the double harmonic scale.
 It is the same as the harmonic minor scale, except that it has a raised fourth scale degree.
 Its tonal center is slightly ambiguous, due to the large number of half steps.
 Also known as Double Harmonic Minor, or Harmonic Minor ♯ 4, it figures prominently in Eastern European music, particularly in Romani music.
 Melodies based on this scale have an exotic, romantic flavor for listeners accustomed to more typical Western scales.
In music, the Psalms chord is "the famous opening chord" of Igor Stravinsky's "Symphony of Psalms", a "barking E minor triad – characteristically spaced", "like no E-minor triad that was ever known before".
 It is common to both the octatonic scale and the Phrygian scale on E, and the contrasting sections of the first movement based on the scales are linked by statements of the Psalms chord.
In music or music theory, the supertonic is the second degree or note of a diatonic scale, one step above the tonic.
 It is sung as re in solfege.
 In music theory, the supertonic chord may be symbolized by the Roman numeral ii in a major scale, indicating that the chord is a minor chord (for example, D-F-A in C major), or ii in a natural minor scale, indicating that the chord is a diminished chord (for example, D-F-A♭ in C natural minor), if in second inversion a six-four chord (A♭ -D-F), and if the third is raised an augmented sixth chord (A♭ -F♯ ).
 If in major or minor, through the lowering of the second scale degree (also the sixth in major), the chord is major (D♭ -F-A♭ ) then it is a Neapolitan 6th chord, N or ♭ II.
 The supertonic may be raised as part of the common-tone diminished seventh chord, ♯ ii .
Ernő Lendvai (February 6, 1925 – January 31, 1993) was one of the first music theorists to write on the appearance of the golden section and Fibonacci series and how these are implemented in Bartók's music.
 He also formulated the axis system, acoustic scale and alpha chord.
The escala nordestina (Portuguese: ""Northeastern scale"" ) are a body of musical scales commonly used in the music of the Nordeste, the northeastern region of Brazil.
 The term can apply to several different scales, including the Mixolydian, the Lydian with a flattened seventh (see Acoustic scale), or the Dorian.
 These three modes have in common the rejection of the use of the major seventh as the leading-tone, generally preferring the more "acoustic and natural" minor seventh.
 The term "northeastern scale" is most commonly used to refer to the Mixolydian mode, which is extensively used in baião and frevo music.
 In Brazilian music, the Dorian mode is formed from the Mixolydian mode, by the lowering of the third, thus being a minor version of the former.
 The Brazilian Lydian, somewhat less common in practice, is a synthetic scale closely related to the harmonic series.
In music, an augmented major seventh chord, or major seventh sharp five chord, or simply augmented seventh chord (written as aug, aug, +, +, +, M, M, M, M, etc.) is a nondominant seventh chord comprising the root note, the note a major third above the root, the note an augmented fifth above the root, and the note a major seventh above the root: 1–3–♯ 5–7, and is associated with the augmented scale (see jazz scale and chord-scale system).
 When used in jazz scores, a number of symbols can be used to represent this chord, including maj+, and Δ +.
The scale of harmonics is a musical scale based on the noded positions of the natural harmonics existing on a string.
 This musical scale is present on the guqin, regarded as one of the first string instruments with a musical scale.
 Most fret positions appearing on Non-Western string instruments (lutes) are equal to positions of this scale.
 Unexpectedly, these fret positions are actually the corresponding undertones of the overtones from the harmonic series.
 The distance from the nut to the fret is an integer number lower than the distance from the fret to the bridge (see: superparticular number).
In music, Roman numeral analysis uses Roman numerals to represent chords.
 The Roman numerals (I, II, III, IV, ...) denote scale degrees (first, second, third, fourth, ...); used to represent a chord, they denote the root note on which the chord is built.
 For instance, III denotes the third degree of a scale or the chord built on it.
 Generally, uppercase Roman numerals (such as I, IV, V) represent major chords while lowercase Roman numerals (such as i, iv, v) represent minor chords (see Major and Minor below for alternative notations); elsewhere, upper-case Roman numerals are used for all chords.
 In Western classical music in the 2000s, Roman numeral analysis is used by music students and music theorists to analyze the harmony of a song or piece.
An octatonic scale is any eight-note musical scale.
 The scale most often meant by this term is one in which the notes ascend in alternating intervals of a whole step and a half step, creating a symmetric scale.
 In classical theory, in contradistinction to jazz theory, this scale is commonly simply called the octatonic scale (or octatonic collection), although there are forty-two other non-enharmonically equivalent, non-transpositionally equivalent eight-tone sets possible.
In music, the axis system is a system of analysis originating in the work of Ernő Lendvai, which he developed in his analysis of the music of Béla Bartók.