Tomohiko Sakamoto’s algorithm
E638639
Tomohiko Sakamoto’s algorithm is a compact, table-based method for calculating the day of the week for any given date in the Gregorian calendar.
All labels observed (1)
| Label | Occurrences |
|---|---|
| Tomohiko Sakamoto’s algorithm canonical | 2 |
How this entity was disambiguated
This entity first appeared as the object of triple T7030557 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: Tomohiko Sakamoto’s algorithm Context triple: [Conway’s Doomsday algorithm, relatedTo, Tomohiko Sakamoto’s algorithm]
-
A.
Zeller’s congruence
Zeller’s congruence is a mathematical formula used to determine the day of the week for any given date in the Gregorian or Julian calendar.
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B.
Conway’s Doomsday algorithm
Conway’s Doomsday algorithm is a mental calculation method devised by mathematician John Horton Conway for quickly determining the day of the week for any given date.
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C.
Gregorian computus
Gregorian computus is the method used in the Gregorian calendar to calculate the date of Easter each year based on a refined solar and lunar cycle.
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D.
proleptic Gregorian calendar
The proleptic Gregorian calendar is the extension of the modern Gregorian dating system backward in time to dates before its historical introduction in 1582.
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E.
Long Count calendar
The Long Count calendar is an ancient Mesoamerican timekeeping system, most notably used by the Maya, that tracks days in a linear count from a mythological starting point to record historical and cosmological events.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: Tomohiko Sakamoto’s algorithm Target entity description: Tomohiko Sakamoto’s algorithm is a compact, table-based method for calculating the day of the week for any given date in the Gregorian calendar.
-
A.
Zeller’s congruence
Zeller’s congruence is a mathematical formula used to determine the day of the week for any given date in the Gregorian or Julian calendar.
-
B.
Conway’s Doomsday algorithm
Conway’s Doomsday algorithm is a mental calculation method devised by mathematician John Horton Conway for quickly determining the day of the week for any given date.
-
C.
Gregorian computus
Gregorian computus is the method used in the Gregorian calendar to calculate the date of Easter each year based on a refined solar and lunar cycle.
-
D.
proleptic Gregorian calendar
The proleptic Gregorian calendar is the extension of the modern Gregorian dating system backward in time to dates before its historical introduction in 1582.
-
E.
Long Count calendar
The Long Count calendar is an ancient Mesoamerican timekeeping system, most notably used by the Maya, that tracks days in a linear count from a mythological starting point to record historical and cosmological events.
- F. None of above. chosen
Statements (42)
| Predicate | Object |
|---|---|
| instanceOf |
algorithm
ⓘ
date calculation algorithm ⓘ day-of-week algorithm ⓘ |
| advantage |
requires only a small lookup table
ⓘ
simple integer arithmetic only ⓘ |
| appliesTo |
Gregorian calendar
ⓘ
linked to:
Gregorian calendar (Western churches)
|
| assumes | proleptic Gregorian calendar for all years in implementation ⓘ |
| basedOn | modular arithmetic ⓘ |
| category | calendar algorithm ⓘ |
| characteristic |
compact implementation
ⓘ
constant time complexity ⓘ table-based method ⓘ uses month offset table ⓘ |
| commonUse |
calendar utilities
ⓘ
date libraries ⓘ embedded systems date calculations ⓘ |
| comparedTo |
Doomsday rule
ⓘ
linked to:
Conway’s Doomsday algorithm
Zeller’s congruence ⓘ |
| creator | Tomohiko Sakamoto ⓘ |
| handles | leap years in the Gregorian calendar ⓘ |
| implementationLanguage | C ⓘ |
| input |
day
ⓘ
month ⓘ year ⓘ |
| mapsTo | weekday index 0–6 ⓘ |
| output | day of the week ⓘ |
| property |
deterministic
ⓘ
does not require floating-point arithmetic ⓘ non-iterative ⓘ |
| requires | integer division and modulo operations ⓘ |
| suitableFor |
programming contest solutions
ⓘ
resource-constrained environments ⓘ |
| timeComplexity | O(1) ⓘ |
| typicalConvention |
0 = Sunday
ⓘ
1 = Monday ⓘ 2 = Tuesday ⓘ 3 = Wednesday ⓘ 4 = Thursday ⓘ 5 = Friday ⓘ 6 = Saturday ⓘ |
| usedFor |
calculating the day of the week
ⓘ
computing weekday from a Gregorian calendar date ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: Tomohiko Sakamoto’s algorithm Description of subject: Tomohiko Sakamoto’s algorithm is a compact, table-based method for calculating the day of the week for any given date in the Gregorian calendar.
Referenced by (2)
Full triples — surface form annotated when it differs from this entity's canonical label.