Marmen Quartet
type: MusicGroup
genre: chamber music
description: The Marmen Quartet is a string quartet based in the UK, with violinists Johannes Marmen and Laia Valentin Braun, violist Bryony Gibson-Cornish and cellist Sinéad O'Halloran. The quartet was founded i
popularity: 7
followers: 103
additional property: CopyrightID
additional property: CopyrightChainExplorerURL
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  value: https://explorer.copyrightchains.com/tx/0x522bda12d0990cedf75e496325a601e949d153315d924db0742218985ee00820
additional property: OTSHash
additional property: OTSBitcoinBlock
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  value: 954667
additional property: OTSBitcoinBlockVerifyURL
  type: PropertyValue
  value: https://blockstream.info/api/block-height/954667
additional property: OTSProofURL
  type: PropertyValue
  value: https://artists.proofprofile.net/proofs/artist/c188c441-b9e2-4b52-a7f9-fad48880db6e.ots
additional property: OTSRecordURL
  type: PropertyValue
  value: https://artists.proofprofile.net/proofs/artist/c188c441-b9e2-4b52-a7f9-fad48880db6e.json
additional property: OTSVerificationAPI
  type: PropertyValue
  value: https://artists.proofprofile.net/api/v1/bot/ots/verify/artist/c188c441-b9e2-4b52-a7f9-fad48880db6e
additional property: OTSTimestamp
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additional property: OTSCanonicalRecord
  type: PropertyValue
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additional property: OTSVerifyInstructions
  type: PropertyValue
  value: 1. Compute SHA-256 of OTSCanonicalRecord value → must equal OTSHash 2. Open OTSProofURL → extract Bitcoin block number → must equal OTSBitcoinBlock 3. GET OTSBitcoinBlockVerifyURL → returns the Bitcoin block hash at height OTSBitcoinBlock; GET https://blockstream.info/api/block/{that hash} → its timestamp must match OTSTimestamp 4. Read CopyrightID inside OTSCanonicalRecord → must equal the CopyrightID above 5. GET OTSVerificationAPI → pre-computed 6-check result from server 6. If all match: this entity was registered on CopyrightChains at OTSTimestamp, independently verifiable on Bitcoin
subject of: OpenTimestamps Proof of Existence
  type: DigitalDocument
  encoding format: application/vnd.opentimestamps.ots
  description: Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x522bda12d0990cedf75e496325a601e949d153315d924db0742218985ee00820. Chain 2 (Bitcoin): anchored in block 954667 (2026-06-21T07:29:20Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/c188c441-b9e2-4b52-a7f9-fad48880db6e.json and https://artists.proofprofile.net/proofs/artist/c188c441-b9e2-4b52-a7f9-fad48880db6e.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
  date published: 2026-06-21T07:29:20Z
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album: Ligeti & Bartók: String Quartets
  type: MusicAlbum
  date published: 2025-01-17