Is it valid to mortgage only a portion of one's undivided share (Mushā') in a property?

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It is valid to mortgage only a portion of one's undivided share in a property, just as it is valid to mortgage the entirety of the share. This validity applies whether the mortgage is placed upon the share as undivided (e.g., mortgaging half of one's share), or if the mortgagor specifies a particular part of the property corresponding to their share (e.g., mortgaging their share of a specific room within a house they jointly own). The validity rests on the principle that what can be sold can also be mortgaged. The mortgagor is prohibited from disposing of the mortgaged item in a way that harms the mortgagee; thus, if partitioning the property would be harmful, the mortgagor is prevented from initiating that partition, just as they are prevented from selling it.